diff --git a/BeefLibs/Beefy2D/src/widgets/WidgetWindow.bf b/BeefLibs/Beefy2D/src/widgets/WidgetWindow.bf
index c177c655..59da888c 100644
--- a/BeefLibs/Beefy2D/src/widgets/WidgetWindow.bf
+++ b/BeefLibs/Beefy2D/src/widgets/WidgetWindow.bf
@@ -23,6 +23,7 @@ namespace Beefy.widgets
         public Event<MouseLeftWindowHandler> mOnMouseLeftWindow ~ _.Dispose();
         public Event<WindowLostFocusHandler> mOnWindowLostFocus ~ _.Dispose();
         public Event<MouseEventHandler> mOnMouseDown ~ _.Dispose();
+		public Event<MouseEventHandler> mOnMouseUp ~ _.Dispose();
         public Event<WindowCloseQueryHandler> mOnWindowCloseQuery ~ _.Dispose();
         public Event<WindowClosedHandler> mOnWindowClosed ~ _.Dispose();
         public Event<WindowMovedHandler> mOnWindowMoved ~ _.Dispose();
@@ -653,12 +654,17 @@ namespace Beefy.widgets
                 anEvent.mSender = this;
                 anEvent.mX = x;
                 anEvent.mY = y;
+				anEvent.mBtn = btn;
+				anEvent.mBtnCount = btnCount;
                 mOnMouseDown(anEvent);
                 sOnMouseDown(anEvent);
                 if (anEvent.mHandled)
                     return;
             }
-            
+
+			if (btn >= 3) // X button - don't pass on to widgets
+				return;
+
             Widget aWidget = mCaptureWidget ?? mOverWidget;
             if (aWidget != null)
             {
@@ -679,6 +685,26 @@ namespace Beefy.widgets
 
 			MouseMove(inX, inY);
             mMouseFlags &= (MouseFlag)(~(1 << btn));
+
+			float x;
+			float y;
+			TranslateMouseCoords(inX, inY, out x, out y);
+
+			if (mOnMouseUp.HasListeners)
+			{
+			    MouseEvent anEvent = scope MouseEvent();
+			    anEvent.mSender = this;
+			    anEvent.mX = x;
+			    anEvent.mY = y;
+				anEvent.mBtn = btn;
+			    mOnMouseUp(anEvent);
+			    if (anEvent.mHandled)
+			        return;
+			}
+
+			if (btn >= 3) // X button - don't pass on to widgets
+				return;
+
             Widget aWidget = mCaptureWidget ?? mOverWidget;
             if (aWidget != null)
             {
diff --git a/BeefySysLib/platform/win/WinBFApp.cpp b/BeefySysLib/platform/win/WinBFApp.cpp
index b307e395..513c7db2 100644
--- a/BeefySysLib/platform/win/WinBFApp.cpp
+++ b/BeefySysLib/platform/win/WinBFApp.cpp
@@ -531,13 +531,15 @@ LRESULT WinBFWindow::WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lPar
 		case WM_LBUTTONDOWN:		
 		case WM_RBUTTONDOWN:
 		case WM_MBUTTONDOWN:
+		case WM_XBUTTONDOWN:
 		case WM_LBUTTONDBLCLK:
 		case WM_RBUTTONDBLCLK:
 		case WM_LBUTTONUP:		
 		case WM_RBUTTONUP:		
 		case WM_MBUTTONUP:
+		case WM_XBUTTONUP:
 		case WM_MOUSEWHEEL:
-		case WM_MOUSEMOVE:	
+		case WM_MOUSEMOVE:
 			{				
 				int x = (short)LOWORD(lParam);
 				int y = (short)HIWORD(lParam);
@@ -602,7 +604,10 @@ LRESULT WinBFWindow::WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lPar
 					break;
 				case WM_MBUTTONDOWN:
 					_BtnDown(2);
-					break;				
+					break;			
+				case WM_XBUTTONDOWN:
+					_BtnDown((int)(wParam >> 16) + 2);
+					break;
 				case WM_LBUTTONUP:
 					_BtnUp(0);					
 					break;
@@ -611,7 +616,10 @@ LRESULT WinBFWindow::WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lPar
 					break;
 				case WM_MBUTTONUP:							
 					_BtnUp(2);
-					break;			
+					break;							
+				case WM_XBUTTONUP:
+					_BtnUp((int)(wParam >> 16) + 2);
+					break;
 				case WM_MOUSEWHEEL:
 					{
 						WinBFWindow* cursorWindow = this;
diff --git a/IDE/src/IDEApp.bf b/IDE/src/IDEApp.bf
index 9db1267c..c8a5c899 100644
--- a/IDE/src/IDEApp.bf
+++ b/IDE/src/IDEApp.bf
@@ -5308,6 +5308,7 @@ namespace IDE
         public void SetupNewWindow(WidgetWindow window, bool isMainWindow)
         {
             window.mOnWindowKeyDown.Add(new => SysKeyDown);
+			window.mOnMouseUp.Add(new => MouseUp);
 			if (isMainWindow)
             	window.mOnWindowCloseQuery.Add(new => SecondaryAllowClose);
         }        
@@ -7087,6 +7088,14 @@ namespace IDE
 			gApp.mSettings.mUISettings.mScale = DarkTheme.sScale * 100.0f;
 		}
 
+		void MouseUp(MouseEvent evt)
+		{
+			if (evt.mBtn == 3)
+				NavigateBackwards();
+			else if (evt.mBtn == 4)
+				NavigateForwards();
+		}
+
         void SysKeyDown(KeyDownEvent evt)
         {
 			if (evt.mHandled)
@@ -10996,6 +11005,7 @@ namespace IDE
 			UpdateTitle();
             mMainWindow.SetMinimumSize(GS!(480), GS!(360));
             mMainWindow.mIsMainWindow = true;
+			mMainWindow.mOnMouseUp.Add(new => MouseUp);
             mMainWindow.mOnWindowKeyDown.Add(new => SysKeyDown);
             mMainWindow.mOnWindowCloseQuery.Add(new => AllowClose);
             CreateMenu();