source typo fixes pt5

+ cleaning up some more non-short-URLs
Issue #2914

src/Gui/SoFCUnifiedSelection.cpp

@@ -538,7 +538,7 @@ void SoFCUnifiedSelection::GLRenderBelowPath(SoGLRenderAction * action)
 
     // nothing picked, so restore the arrow cursor if needed
     if (this->preSelection == 0) {
-        // this is called when a selection gate forbad to select an object
+        // this is called when a selection gate forbade to select an object
         // and the user moved the mouse to an empty area
         this->preSelection = -1;
         QGLWidget* window;