Move method for Rectangle class.

Ensure windows that are moved are not moved off screen to the top or left.

2 files changed, 13 insertions, 4 deletions

diff --git a/include/Platform.h b/include/Platform.h
index 5ad782c03..db3cd6c7d 100644
--- a/include/Platform.h
+++ b/include/Platform.h
@@ -104,6 +104,12 @@ public:
 		return (right > other.left) && (left < other.right) &&
 			(bottom > other.top) && (top < other.bottom);
 	}
+	void Move(int xDelta, int yDelta) {
+		left += xDelta;
+		top += yDelta;
+		right += xDelta;
+		bottom += yDelta;
+	}
 	int Width() { return right - left; }
 	int Height() { return bottom - top; }
 };
diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 09bf83ded..d2b88bda3 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -769,10 +769,13 @@ void Window::SetPositionRelative(PRectangle rc, Window w) {
 	if (style & WS_POPUP) {
 		RECT rcOther;
 		::GetWindowRect(reinterpret_cast<HWND>(w.GetID()), &rcOther);
-		rc.top += rcOther.top;
-		rc.left += rcOther.left;
-		rc.bottom += rcOther.top;
-		rc.right += rcOther.left;
+		rc.Move(rcOther.left, rcOther.top);
+		if (rc.left < 0) {
+			rc.Move(-rc.left,0);
+		}
+		if (rc.top < 0) {
+			rc.Move(0,-rc.top);
+		}
 	}
 	SetPosition(rc);
 }