diff --git a/src/d_main.cpp b/src/d_main.cpp
index ab0828009..6d16ccc4b 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -680,10 +680,10 @@ void D_Display ()
 	// fullscreen toggle has been requested
 	if (setmodeneeded)
 	{
+		setmodeneeded = false;
 		screen->ToggleFullscreen(fullscreen);
 		V_OutputResized(screen->GetWidth(), screen->GetHeight());
-		setmodeneeded = false;
-			}
+	}
 
 	// change the view size if needed
 	if (setsizeneeded)
diff --git a/src/v_video.cpp b/src/v_video.cpp
index fbb0109a2..77d13d1a9 100644
--- a/src/v_video.cpp
+++ b/src/v_video.cpp
@@ -857,6 +857,20 @@ void ScaleWithAspect (int &w, int &h, int Width, int Height)
 		h = static_cast<int>(y);
 }
 
+CCMD(vid_setsize)
+{
+	if (argv.argc() < 2)
+	{
+		Printf("Usage: vid_setsize width height\n");
+	}
+	else
+	{
+		screen->SetWindowSize((int)strtol(argv[1], nullptr, 0), (int)strtol(argv[2], nullptr, 0));
+		V_OutputResized(screen->GetClientWidth(), screen->GetClientHeight());
+	}
+}
+
+
 void IVideo::DumpAdapters ()
 {
 	Printf("Multi-monitor support unavailable.\n");
diff --git a/src/v_video.h b/src/v_video.h
index 2e6c0cd30..74d0b0db7 100644
--- a/src/v_video.h
+++ b/src/v_video.h
@@ -423,6 +423,7 @@ public:
 	virtual void UnbindTexUnit(int no) {}
 	virtual void TextureFilterChanged() {}
 	virtual void BeginFrame() {}
+	virtual void SetWindowSize(int w, int h) {}
 
 	virtual int GetClientWidth() = 0;
 	virtual int GetClientHeight() = 0;
diff --git a/src/win32/base_sysfb.cpp b/src/win32/base_sysfb.cpp
index 5e2f5c21e..550eb9639 100644
--- a/src/win32/base_sysfb.cpp
+++ b/src/win32/base_sysfb.cpp
@@ -52,6 +52,7 @@
 #include "doomerrors.h"
 #include "base_sysfb.h"
 #include "win32basevideo.h"
+#include "c_dispatch.h"
 
 
 extern HWND			Window;
@@ -69,6 +70,7 @@ CVAR(Bool, win_maximized, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 
 EXTERN_CVAR(Int, vid_defwidth)
 EXTERN_CVAR(Int, vid_defheight)
+EXTERN_CVAR(Bool, fullscreen)
 
 
 //==========================================================================
@@ -226,6 +228,64 @@ void SystemBaseFrameBuffer::RestoreWindowedPos()
 //
 //==========================================================================
 
+void SystemBaseFrameBuffer::SetWindowSize(int w, int h)
+{
+	if (w < 0 || h < 0)
+	{
+		RestoreWindowedPos();
+	}
+	else
+	{
+		LONG style = WS_VISIBLE | WS_CLIPSIBLINGS | WS_OVERLAPPEDWINDOW;
+		LONG exStyle = WS_EX_WINDOWEDGE;
+		SetWindowLong(Window, GWL_STYLE, style);
+		SetWindowLong(Window, GWL_EXSTYLE, exStyle);
+
+		int winx, winy, winw, winh, scrwidth, scrheight;
+
+		RECT r = { 0, 0, w, h };
+		AdjustWindowRectEx(&r, style, false, exStyle);
+		w = int(r.right - r.left);
+		h = int(r.bottom - r.top);
+
+		GetCenteredPos(w, h, winx, winy, winw, winh, scrwidth, scrheight);
+
+		// Just move to (0,0) if we were run with the -0 option.
+		if (Args->CheckParm("-0"))
+		{
+			winx = winy = 0;
+		}
+		else
+		{
+			KeepWindowOnScreen(winx, winy, winw, winh, scrwidth, scrheight);
+		}
+
+		if (!fullscreen)
+		{
+			ShowWindow(Window, SW_SHOWNORMAL);
+			SetWindowPos(Window, nullptr, winx, winy, winw, winh, SWP_NOZORDER | SWP_FRAMECHANGED);
+			win_maximized = false;
+			SetSize(GetClientWidth(), GetClientHeight());
+			SaveWindowedPos();
+		}
+		else
+		{
+			win_x = winx;
+			win_y = winy;
+			win_w = winw;
+			win_h = winh;
+			win_maximized = false;
+			fullscreen = false;
+		}
+	}
+}
+
+//==========================================================================
+//
+// 
+//
+//==========================================================================
+
 void SystemBaseFrameBuffer::PositionWindow(bool fullscreen)
 {
 	RECT r;
@@ -233,7 +293,7 @@ void SystemBaseFrameBuffer::PositionWindow(bool fullscreen)
 
 	RECT monRect;
 
-	if (!m_Fullscreen) SaveWindowedPos();
+	if (!m_Fullscreen && fullscreen) SaveWindowedPos();
 	if (m_Monitor)
 	{
 		MONITORINFOEX mi;
@@ -264,7 +324,6 @@ void SystemBaseFrameBuffer::PositionWindow(bool fullscreen)
 	SetWindowLong(Window, GWL_STYLE, style);
 	SetWindowLong(Window, GWL_EXSTYLE, exStyle);
 
-	m_Fullscreen = fullscreen;
 	if (fullscreen)
 	{
 		SetWindowPos(Window, 0, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
@@ -275,7 +334,14 @@ void SystemBaseFrameBuffer::PositionWindow(bool fullscreen)
 	else
 	{
 		RestoreWindowedPos();
+		// This doesn't restore the window size properly so we must force a set size the next tic.
+		if (m_Fullscreen)
+		{
+			::fullscreen = false;
+		}
+
 	}
+	m_Fullscreen = fullscreen;
 	SetSize(GetClientWidth(), GetClientHeight());
 }
 
@@ -306,7 +372,7 @@ SystemBaseFrameBuffer::SystemBaseFrameBuffer(void *hMonitor, bool fullscreen) :
 SystemBaseFrameBuffer::~SystemBaseFrameBuffer()
 {
 	ResetGammaTable();
-	SaveWindowedPos();
+	if (!m_Fullscreen) SaveWindowedPos();
 
 	ShowWindow (Window, SW_SHOW);
 	SetWindowLong(Window, GWL_STYLE, WS_VISIBLE | WS_CLIPSIBLINGS | WS_OVERLAPPEDWINDOW);
diff --git a/src/win32/base_sysfb.h b/src/win32/base_sysfb.h
index 01672c280..84eb5c981 100644
--- a/src/win32/base_sysfb.h
+++ b/src/win32/base_sysfb.h
@@ -21,6 +21,7 @@ public:
 
 	bool IsFullscreen() override;
 	void ToggleFullscreen(bool yes) override;
+	void SetWindowSize(int client_w, int client_h);
 
 protected:
 
@@ -35,7 +36,7 @@ protected:
 	float m_Gamma, m_Brightness, m_Contrast;
 	uint16_t m_origGamma[768];
 	bool m_supportsGamma;
-	bool m_Fullscreen;
+	bool m_Fullscreen = false;
 	char m_displayDeviceNameBuffer[32/*CCHDEVICENAME*/];	// do not use windows.h constants here!
 	char *m_displayDeviceName;
 	void *m_Monitor;