diff --git a/src/openrct2-ui/interface/Window.cpp b/src/openrct2-ui/interface/Window.cpp
new file mode 100644
index 0000000000..0e06671227
--- /dev/null
+++ b/src/openrct2-ui/interface/Window.cpp
@@ -0,0 +1,267 @@
+#include <openrct2/audio/audio.h>
+#include <openrct2/config/Config.h>
+#include <openrct2/Context.h>
+#include <openrct2/interface/themes.h>
+#include <openrct2/OpenRCT2.h>
+#include <openrct2/world/Sprite.h>
+#include <openrct2/ui/UiContext.h>
+#include "Window.h"
+
+#define RCT2_NEW_WINDOW         (gWindowNextSlot)
+#define RCT2_LAST_WINDOW        (gWindowNextSlot - 1)
+
+using namespace OpenRCT2;
+
+static bool window_fits_between_others(sint32 x, sint32 y, sint32 width, sint32 height)
+{
+    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
+        if (w->flags & WF_STICK_TO_BACK)
+            continue;
+
+        if (x + width <= w->x) continue;
+        if (x >= w->x + w->width) continue;
+        if (y + height <= w->y) continue;
+        if (y >= w->y + w->height) continue;
+        return false;
+    }
+
+    return true;
+}
+
+static bool window_fits_within_space(sint32 x, sint32 y, sint32 width, sint32 height)
+{
+    if (x < 0) return false;
+    if (y <= TOP_TOOLBAR_HEIGHT && !(gScreenFlags & SCREEN_FLAGS_TITLE_DEMO)) return false;
+    if (x + width > context_get_width()) return false;
+    if (y + height > context_get_height()) return false;
+    return window_fits_between_others(x, y, width, height);
+}
+
+static bool window_fits_on_screen(sint32 x, sint32 y, sint32 width, sint32 height)
+{
+    uint16 screenWidth = context_get_width();
+    uint16 screenHeight = context_get_height();
+    sint32 unk;
+
+    unk = -(width / 4);
+    if (x < unk) return false;
+    unk = screenWidth + (unk * 2);
+    if (x > unk) return false;
+    if (y <= TOP_TOOLBAR_HEIGHT && !(gScreenFlags & SCREEN_FLAGS_TITLE_DEMO)) return false;
+    unk = screenHeight - (height / 4);
+    if (y > unk) return false;
+    return window_fits_between_others(x, y, width, height);
+}
+
+rct_window *window_create(sint32 x, sint32 y, sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
+{
+    // Check if there are any window slots left
+    // include WINDOW_LIMIT_RESERVED for items such as the main viewport and toolbars to not appear to be counted.
+    if (RCT2_NEW_WINDOW >= &(g_window_list[gConfigGeneral.window_limit + WINDOW_LIMIT_RESERVED])) {
+        rct_window *w = nullptr;
+        // Close least recently used window
+        for (w = g_window_list; w < RCT2_NEW_WINDOW; w++)
+            if (!(w->flags & (WF_STICK_TO_BACK | WF_STICK_TO_FRONT | WF_NO_AUTO_CLOSE)))
+                break;
+
+        window_close(w);
+    }
+
+    rct_window *w = RCT2_NEW_WINDOW;
+
+    // Flags
+    if (flags & WF_STICK_TO_BACK) {
+        for (; w >= g_window_list + 1; w--) {
+            if ((w - 1)->flags & WF_STICK_TO_FRONT)
+                continue;
+            if ((w - 1)->flags & WF_STICK_TO_BACK)
+                break;
+        }
+    }
+    else if (!(flags & WF_STICK_TO_FRONT)) {
+        for (; w >= g_window_list + 1; w--) {
+            if (!((w - 1)->flags & WF_STICK_TO_FRONT))
+                break;
+        }
+    }
+
+    // Move w to new window slot
+    if (w != RCT2_NEW_WINDOW)
+        *RCT2_NEW_WINDOW = *w;
+
+    // Setup window
+    w->classification = cls;
+    w->var_4B8 = -1;
+    w->var_4B9 = -1;
+    w->flags = flags;
+
+    // Play sounds and flash the window
+    if (!(flags & (WF_STICK_TO_BACK | WF_STICK_TO_FRONT))) {
+        w->flags |= WF_WHITE_BORDER_MASK;
+        audio_play_sound(SOUND_WINDOW_OPEN, 0, x + (width / 2));
+    }
+
+    w->number = 0;
+    w->x = x;
+    w->y = y;
+    w->width = width;
+    w->height = height;
+    w->viewport = nullptr;
+    w->event_handlers = event_handlers;
+    w->enabled_widgets = 0;
+    w->disabled_widgets = 0;
+    w->pressed_widgets = 0;
+    w->hold_down_widgets = 0;
+    w->viewport_focus_coordinates.var_480 = 0;
+    w->viewport_focus_coordinates.x = 0;
+    w->viewport_focus_coordinates.y = 0;
+    w->viewport_focus_coordinates.z = 0;
+    w->viewport_focus_coordinates.rotation = 0;
+    w->page = 0;
+    w->var_48C = 0;
+    w->frame_no = 0;
+    w->list_information_type = 0;
+    w->var_492 = 0;
+    w->selected_tab = 0;
+    w->var_4AE = 0;
+    w->viewport_smart_follow_sprite = SPRITE_INDEX_NULL;
+    RCT2_NEW_WINDOW++;
+
+    colour_scheme_update(w);
+    window_invalidate(w);
+    return w;
+}
+
+rct_window *window_create_auto_pos(sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
+{
+    auto uiContext = GetContext()->GetUiContext();
+    auto screenWidth = uiContext->GetWidth();
+    auto screenHeight = uiContext->GetHeight();
+
+    // TODO dead code, looks like it is cascading the new window offset from an existing window
+    // we will have to re-implement this in our own way.
+    //
+    // if (cls & 0x80) {
+    //  cls &= ~0x80;
+    //  rct_window *w = window_find_by_number(0, 0);
+    //  if (w != nullptr) {
+    //      if (w->x > -60 && w->x < screenWidth - 20) {
+    //          if (w->y < screenHeight - 20) {
+    //              sint32 x = w->x;
+    //              if (w->x + width > screenWidth)
+    //                  x = screenWidth - 20 - width;
+    //              sint32 y = w->y;
+    //              return window_create(x + 10, y + 10, width, height, event_handlers, cls, flags);
+    //          }
+    //      }
+    //  }
+    // }
+
+    // Place window in an empty corner of the screen
+    sint32 x = 0;
+    sint32 y = 30;
+    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+    x = screenWidth - width;
+    y = 30;
+    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+    x = 0;
+    y = screenHeight - 34 - height;
+    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+    x = screenWidth - width;
+    y = screenHeight - 34 - height;
+    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+    // Place window next to another
+    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
+        if (w->flags & WF_STICK_TO_BACK)
+            continue;
+
+        x = w->x + w->width + 2;
+        y = w->y;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x - w->width - 2;
+        y = w->y;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x;
+        y = w->y + w->height + 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x;
+        y = w->y - w->height - 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x + w->width + 2;
+        y = w->y - w->height - 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x - w->width - 2;
+        y = w->y - w->height - 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x + w->width + 2;
+        y = w->y + w->height + 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+
+        x = w->x - w->width - 2;
+        y = w->y + w->height + 2;
+        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
+    }
+
+    // Overlap
+    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
+        if (w->flags & WF_STICK_TO_BACK)
+            continue;
+
+        x = w->x + w->width + 2;
+        y = w->y;
+        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
+
+        x = w->x - w->width - 2;
+        y = w->y;
+        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
+
+        x = w->x;
+        y = w->y + w->height + 2;
+        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
+
+        x = w->x;
+        y = w->y - w->height - 2;
+        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
+    }
+
+    // Cascade
+    x = 0;
+    y = 30;
+    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
+        if (x != w->x || y != w->y)
+            continue;
+
+        x += 5;
+        y += 5;
+    }
+
+    // Clamp to inside the screen
+foundSpace:
+    if (x < 0)
+        x = 0;
+    if (x + width > screenWidth)
+        x = screenWidth - width;
+
+    return window_create(x, y, width, height, event_handlers, cls, flags);
+}
+
+rct_window * window_create_centred(sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
+{
+    auto uiContext = GetContext()->GetUiContext();
+    auto screenWidth = uiContext->GetWidth();
+    auto screenHeight = uiContext->GetHeight();
+
+    sint32 x = (screenWidth - width) / 2;
+    sint32 y = std::max(TOP_TOOLBAR_HEIGHT + 1, (screenHeight - height) / 2);
+    return window_create(x, y, width, height, event_handlers, cls, flags);
+}
diff --git a/src/openrct2/interface/Window.cpp b/src/openrct2/interface/Window.cpp
index a5839ec0b8..f19cc51ce4 100644
--- a/src/openrct2/interface/Window.cpp
+++ b/src/openrct2/interface/Window.cpp
@@ -26,7 +26,6 @@
 #include "../Game.h"
 #include "../Input.h"
 #include "../interface/Cursors.h"
-#include "../interface/themes.h"
 #include "../localisation/Localisation.h"
 #include "../localisation/StringIds.h"
 #include "../OpenRCT2.h"
@@ -426,306 +425,6 @@ void window_set_window_limit(sint32 value)
     }
 }
 
-/**
- * Opens a new window.
- *  rct2: 0x006EACA4
- *
- * @param x (ax)
- * @param y (eax >> 16)
- * @param width (bx)
- * @param height (ebx >> 16)
- * @param events (edx)
- * @param flags (ch)
- * @param class (cl)
- */
-rct_window *window_create(sint32 x, sint32 y, sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
-{
-    // Check if there are any window slots left
-    // include WINDOW_LIMIT_RESERVED for items such as the main viewport and toolbars to not appear to be counted.
-    if (RCT2_NEW_WINDOW >= &(g_window_list[gConfigGeneral.window_limit + WINDOW_LIMIT_RESERVED])) {
-        rct_window *w = nullptr;
-        // Close least recently used window
-        for (w = g_window_list; w < RCT2_NEW_WINDOW; w++)
-            if (!(w->flags & (WF_STICK_TO_BACK | WF_STICK_TO_FRONT | WF_NO_AUTO_CLOSE)))
-                break;
-
-        window_close(w);
-    }
-
-    rct_window *w = RCT2_NEW_WINDOW;
-
-    // Flags
-    if (flags & WF_STICK_TO_BACK) {
-        for (; w >= g_window_list + 1; w--) {
-            if ((w - 1)->flags & WF_STICK_TO_FRONT)
-                continue;
-            if ((w - 1)->flags & WF_STICK_TO_BACK)
-                break;
-        }
-    } else if (!(flags & WF_STICK_TO_FRONT)) {
-        for (; w >= g_window_list + 1; w--) {
-            if (!((w - 1)->flags & WF_STICK_TO_FRONT))
-                break;
-        }
-    }
-
-    // Move w to new window slot
-    if (w != RCT2_NEW_WINDOW)
-        *RCT2_NEW_WINDOW = *w;
-
-    // Setup window
-    w->classification = cls;
-    w->var_4B8 = -1;
-    w->var_4B9 = -1;
-    w->flags = flags;
-
-    // Play sounds and flash the window
-    if (!(flags & (WF_STICK_TO_BACK | WF_STICK_TO_FRONT))){
-        w->flags |= WF_WHITE_BORDER_MASK;
-        audio_play_sound(SOUND_WINDOW_OPEN, 0, x + (width / 2));
-    }
-
-    w->number = 0;
-    w->x = x;
-    w->y = y;
-    w->width = width;
-    w->height = height;
-    w->viewport = nullptr;
-    w->event_handlers = event_handlers;
-    w->enabled_widgets = 0;
-    w->disabled_widgets = 0;
-    w->pressed_widgets = 0;
-    w->hold_down_widgets = 0;
-    w->viewport_focus_coordinates.var_480 = 0;
-    w->viewport_focus_coordinates.x = 0;
-    w->viewport_focus_coordinates.y = 0;
-    w->viewport_focus_coordinates.z = 0;
-    w->viewport_focus_coordinates.rotation = 0;
-    w->page = 0;
-    w->var_48C = 0;
-    w->frame_no = 0;
-    w->list_information_type = 0;
-    w->var_492 = 0;
-    w->selected_tab = 0;
-    w->var_4AE = 0;
-    w->viewport_smart_follow_sprite = SPRITE_INDEX_NULL;
-    RCT2_NEW_WINDOW++;
-
-    colour_scheme_update(w);
-    window_invalidate(w);
-    return w;
-}
-
-/**
- *
- *  rct2: 0x006EA934
- *
- * @param x (dx)
- * @param y (ax)
- * @param width (bx)
- * @param height (cx)
- */
-static bool window_fits_on_screen(sint32 x, sint32 y, sint32 width, sint32 height)
-{
-    uint16 screenWidth = context_get_width();
-    uint16 screenHeight = context_get_height();
-    sint32 unk;
-
-    unk = -(width / 4);
-    if (x < unk) return false;
-    unk =  screenWidth + (unk * 2);
-    if (x > unk) return false;
-    if (y <= TOP_TOOLBAR_HEIGHT && !(gScreenFlags & SCREEN_FLAGS_TITLE_DEMO)) return false;
-    unk = screenHeight - (height / 4);
-    if (y > unk) return false;
-    return window_fits_between_others(x, y, width, height);
-}
-
-/**
- *
- *  rct2: 0x006EA934
- *
- * @param x (dx)
- * @param y (ax)
- * @param width (bx)
- * @param height (cx)
- */
-static bool window_fits_within_space(sint32 x, sint32 y, sint32 width, sint32 height)
-{
-    if (x < 0) return false;
-    if (y <= TOP_TOOLBAR_HEIGHT && !(gScreenFlags & SCREEN_FLAGS_TITLE_DEMO)) return false;
-    if (x + width > context_get_width()) return false;
-    if (y + height > context_get_height()) return false;
-    return window_fits_between_others(x, y, width, height);
-}
-
-/**
- *
- *  rct2: 0x006EA934
- *
- * @param x (dx)
- * @param y (ax)
- * @param width (bx)
- * @param height (cx)
- */
-static bool window_fits_between_others(sint32 x, sint32 y, sint32 width, sint32 height)
-{
-    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
-        if (w->flags & WF_STICK_TO_BACK)
-            continue;
-
-        if (x + width <= w->x) continue;
-        if (x >= w->x + w->width) continue;
-        if (y + height <= w->y) continue;
-        if (y >= w->y + w->height) continue;
-        return false;
-    }
-
-    return true;
-}
-
-/**
- * Opens a new window, supposedly automatically positioned
- *  rct2: 0x006EA9B1
- *
- * @param width (bx)
- * @param height (ebx >> 16)
- * @param events (edx)
- * @param flags (ch)
- * @param class (cl)
- */
-rct_window *window_create_auto_pos(sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
-{
-    uint16 screenWidth = context_get_width();
-    uint16 screenHeight = context_get_height();
-
-    // TODO dead code, looks like it is cascading the new window offset from an existing window
-    // we will have to re-implement this in our own way.
-    //
-    // if (cls & 0x80) {
-    //  cls &= ~0x80;
-    //  rct_window *w = window_find_by_number(0, 0);
-    //  if (w != nullptr) {
-    //      if (w->x > -60 && w->x < screenWidth - 20) {
-    //          if (w->y < screenHeight - 20) {
-    //              sint32 x = w->x;
-    //              if (w->x + width > screenWidth)
-    //                  x = screenWidth - 20 - width;
-    //              sint32 y = w->y;
-    //              return window_create(x + 10, y + 10, width, height, event_handlers, cls, flags);
-    //          }
-    //      }
-    //  }
-    // }
-
-    // Place window in an empty corner of the screen
-    sint32 x = 0;
-    sint32 y = 30;
-    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-    x = screenWidth - width;
-    y = 30;
-    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-    x = 0;
-    y = screenHeight - 34 - height;
-    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-    x = screenWidth - width;
-    y = screenHeight - 34 - height;
-    if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-    // Place window next to another
-    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
-        if (w->flags & WF_STICK_TO_BACK)
-            continue;
-
-        x = w->x + w->width + 2;
-        y = w->y;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x - w->width - 2;
-        y = w->y;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x;
-        y = w->y + w->height + 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x;
-        y = w->y - w->height - 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x + w->width + 2;
-        y = w->y - w->height - 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x - w->width - 2;
-        y = w->y - w->height - 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x + w->width + 2;
-        y = w->y + w->height + 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-
-        x = w->x - w->width - 2;
-        y = w->y + w->height + 2;
-        if (window_fits_within_space(x, y, width, height)) goto foundSpace;
-    }
-
-    // Overlap
-    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
-        if (w->flags & WF_STICK_TO_BACK)
-            continue;
-
-        x = w->x + w->width + 2;
-        y = w->y;
-        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
-
-        x = w->x - w->width - 2;
-        y = w->y;
-        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
-
-        x = w->x;
-        y = w->y + w->height + 2;
-        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
-
-        x = w->x;
-        y = w->y - w->height - 2;
-        if (window_fits_on_screen(x, y, width, height)) goto foundSpace;
-    }
-
-    // Cascade
-    x = 0;
-    y = 30;
-    for (rct_window *w = g_window_list; w < RCT2_LAST_WINDOW; w++) {
-        if (x != w->x || y != w->y)
-            continue;
-
-        x += 5;
-        y += 5;
-    }
-
-    // Clamp to inside the screen
-foundSpace:
-    if (x < 0)
-        x = 0;
-    if (x + width > screenWidth)
-        x = screenWidth - width;
-
-    return window_create(x, y, width, height, event_handlers, cls, flags);
-}
-
-rct_window * window_create_centred(sint32 width, sint32 height, rct_window_event_list *event_handlers, rct_windowclass cls, uint16 flags)
-{
-    sint32 screenWidth = context_get_width();
-    sint32 screenHeight = context_get_height();
-
-    sint32 x = (screenWidth - width) / 2;
-    sint32 y = std::max(TOP_TOOLBAR_HEIGHT + 1, (screenHeight - height) / 2);
-    return window_create(x, y, width, height, event_handlers, cls, flags);
-}
-
 /**
  * Closes the specified window.
  *  rct2: 0x006ECD4C