Correct window transparency calculation in wxQT, thanks @seandpagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77931 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/qt/window.cpp

@@ -969,7 +969,7 @@ bool wxWindowQt::IsTransparentBackgroundSupported(wxString* WXUNUSED(reason)) co
 bool wxWindowQt::SetTransparent(wxByte alpha)
 {
     // For Qt, range is between 1 (opaque) and 0 (transparent)
-    GetHandle()->setWindowOpacity(1 - alpha/255.0);
+    GetHandle()->setWindowOpacity(alpha/255.0);
     return true;
 }