diff --git a/core/sys/windows/gdi32.odin b/core/sys/windows/gdi32.odin
index 2caf42753..15d5567c7 100644
--- a/core/sys/windows/gdi32.odin
+++ b/core/sys/windows/gdi32.odin
@@ -14,7 +14,7 @@ foreign gdi32 {
 		hdc: HDC,
 		pbmih: ^BITMAPINFOHEADER,
 		flInit: DWORD,
-		pjBits: ^VOID,
+		pjBits: VOID,
 		pbmi: ^BITMAPINFO,
 		iUsage: UINT,
 	) -> HBITMAP ---
@@ -23,7 +23,7 @@ foreign gdi32 {
 		hdc: HDC,
 		pbmi: ^BITMAPINFO,
 		usage: UINT,
-		ppvBits: ^^VOID,
+		ppvBits: VOID,
 		hSection: HANDLE,
 		offset: DWORD,
 	) -> HBITMAP ---
@@ -38,7 +38,7 @@ foreign gdi32 {
 		ySrc: c_int,
 		SrcWidth: c_int,
 		SrcHeight: c_int,
-		lpBits: ^VOID,
+		lpBits: VOID,
 		lpbmi: ^BITMAPINFO,
 		iUsage: UINT,
 		rop: DWORD,
diff --git a/core/sys/windows/types.odin b/core/sys/windows/types.odin
index 9a4a1ab5e..bd6eba24e 100644
--- a/core/sys/windows/types.odin
+++ b/core/sys/windows/types.odin
@@ -312,6 +312,65 @@ CREATESTRUCTW:: struct {
 	dwExStyle:      DWORD,
 }
 
+// MessageBox() Flags
+MB_OK                :: 0x00000000
+MB_OKCANCEL          :: 0x00000001
+MB_ABORTRETRYIGNORE  :: 0x00000002
+MB_YESNOCANCEL       :: 0x00000003
+MB_YESNO             :: 0x00000004
+MB_RETRYCANCEL       :: 0x00000005
+MB_CANCELTRYCONTINUE :: 0x00000006
+
+MB_ICONHAND        :: 0x00000010
+MB_ICONQUESTION    :: 0x00000020
+MB_ICONEXCLAMATION :: 0x00000030
+MB_ICONASTERISK    :: 0x00000040
+MB_USERICON        :: 0x00000080
+MB_ICONWARNING     :: MB_ICONEXCLAMATION
+MB_ICONERROR       :: MB_ICONHAND
+MB_ICONINFORMATION :: MB_ICONASTERISK
+MB_ICONSTOP        :: MB_ICONHAND
+
+MB_DEFBUTTON1 :: 0x00000000
+MB_DEFBUTTON2 :: 0x00000100
+MB_DEFBUTTON3 :: 0x00000200
+MB_DEFBUTTON4 :: 0x00000300
+
+MB_APPLMODAL   :: 0x00000000
+MB_SYSTEMMODAL :: 0x00001000
+MB_TASKMODAL   :: 0x00002000
+MB_HELP        :: 0x00004000 // Help Button
+
+MB_NOFOCUS              :: 0x00008000
+MB_SETFOREGROUND        :: 0x00010000
+MB_DEFAULT_DESKTOP_ONLY :: 0x00020000
+MB_TOPMOST              :: 0x00040000
+MB_RIGHT                :: 0x00080000
+MB_RTLREADING           :: 0x00100000
+
+MB_SERVICE_NOTIFICATION      :: 0x00200000
+MB_SERVICE_NOTIFICATION_NT3X :: 0x00040000
+
+MB_TYPEMASK :: 0x0000000F
+MB_ICONMASK :: 0x000000F0
+MB_DEFMASK  :: 0x00000F00
+MB_MODEMASK :: 0x00003000
+MB_MISCMASK :: 0x0000C000
+
+// Dialog Box Command IDs
+IDOK       :: 1
+IDCANCEL   :: 2
+IDABORT    :: 3
+IDRETRY    :: 4
+IDIGNORE   :: 5
+IDYES      :: 6
+IDNO       :: 7
+IDCLOSE    :: 8
+IDHELP     :: 9
+IDTRYAGAIN :: 10
+IDCONTINUE :: 11
+IDTIMEOUT  :: 32000
+
 CS_VREDRAW         : UINT : 0x0001
 CS_HREDRAW         : UINT : 0x0002
 CS_DBLCLKS         : UINT : 0x0008
@@ -399,6 +458,30 @@ SW_RESTORE         : c_int : 9
 SW_SHOWDEFAULT     : c_int : 10
 SW_FORCEMINIMIZE   : c_int : 11
 
+// SetWindowPos Flags
+SWP_NOSIZE         :: 0x0001
+SWP_NOMOVE         :: 0x0002
+SWP_NOZORDER       :: 0x0004
+SWP_NOREDRAW       :: 0x0008
+SWP_NOACTIVATE     :: 0x0010
+SWP_FRAMECHANGED   :: 0x0020 // The frame changed: send WM_NCCALCSIZE
+SWP_SHOWWINDOW     :: 0x0040
+SWP_HIDEWINDOW     :: 0x0080
+SWP_NOCOPYBITS     :: 0x0100
+SWP_NOOWNERZORDER  :: 0x0200 // Don't do owner Z ordering
+SWP_NOSENDCHANGING :: 0x0400 // Don't send WM_WINDOWPOSCHANGING
+
+SWP_DRAWFRAME    :: SWP_FRAMECHANGED
+SWP_NOREPOSITION :: SWP_NOOWNERZORDER
+
+SWP_DEFERERASE     :: 0x2000 // same as SWP_DEFERDRAWING
+SWP_ASYNCWINDOWPOS :: 0x4000 // same as SWP_CREATESPB
+
+HWND_TOP       :: 0
+HWND_BOTTOM    :: 1
+HWND_TOPMOST   :: -1
+HWND_NOTOPMOST :: -2
+
 CW_USEDEFAULT      : c_int : -2147483648
 
 SIZE_RESTORED  :: 0
@@ -416,6 +499,15 @@ WMSZ_BOTTOM      :: 6
 WMSZ_BOTTOMLEFT  :: 7
 WMSZ_BOTTOMRIGHT :: 8
 
+// Key State Masks for Mouse Messages
+MK_LBUTTON  :: 0x0001
+MK_RBUTTON  :: 0x0002
+MK_SHIFT    :: 0x0004
+MK_CONTROL  :: 0x0008
+MK_MBUTTON  :: 0x0010
+MK_XBUTTON1 :: 0x0020
+MK_XBUTTON2 :: 0x0040
+
 _IDC_APPSTARTING := rawptr(uintptr(32650))
 _IDC_ARROW       := rawptr(uintptr(32512))
 _IDC_CROSS       := rawptr(uintptr(32515))
@@ -837,6 +929,15 @@ FILE_TYPE_PIPE :: 0x0003
 RECT  :: struct {left, top, right, bottom: LONG}
 POINT :: struct {x, y: LONG}
 
+WINDOWPOS :: struct {
+	hwnd: HWND,
+	hwndInsertAfter: HWND,
+	x: c_int,
+	y: c_int,
+	cx: c_int,
+	cy: c_int,
+	flags: UINT,
+}
 
 when size_of(uintptr) == 4 {
 	WSADATA :: struct {
diff --git a/core/sys/windows/user32.odin b/core/sys/windows/user32.odin
index fc001f26b..2336878ef 100644
--- a/core/sys/windows/user32.odin
+++ b/core/sys/windows/user32.odin
@@ -97,6 +97,15 @@ foreign user32 {
 	LoadCursorW :: proc(hInstance: HINSTANCE, lpCursorName: LPCWSTR) -> HCURSOR ---
 
 	GetClientRect :: proc(hWnd: HWND, lpRect: ^RECT) -> BOOL ---
+	SetWindowPos :: proc(
+		hWnd: HWND,
+		hWndInsertAfter: HWND,
+		X: c_int,
+		Y: c_int,
+		cx: c_int,
+		cy: c_int,
+		uFlags: UINT,
+	) -> BOOL ---
 
 	GetWindowDC :: proc(hWnd: HWND) -> HDC ---
 	GetDC :: proc(hWnd: HWND) -> HDC ---
@@ -111,6 +120,11 @@ foreign user32 {
 
 	GetKeyState :: proc(nVirtKey: c_int) -> SHORT ---
 	GetAsyncKeyState :: proc(vKey: c_int) -> SHORT ---
+
+	MessageBoxA :: proc(hWnd: HWND, lpText: LPCSTR, lpCaption: LPCSTR, uType: UINT) -> c_int ---
+	MessageBoxW :: proc(hWnd: HWND, lpText: LPCWSTR, lpCaption: LPCWSTR, uType: UINT) -> c_int ---
+	MessageBoxExA :: proc(hWnd: HWND, lpText: LPCSTR, lpCaption: LPCSTR, uType: UINT, wLanguageId: WORD) -> c_int ---
+	MessageBoxExW :: proc(hWnd: HWND, lpText: LPCWSTR, lpCaption: LPCWSTR, uType: UINT, wLanguageId: WORD) -> c_int ---
 }
 
 CreateWindowA :: #force_inline proc "stdcall" (