Make wxPG_TOOLTIPS work for >2 columns too

include/wx/propgrid/propgrid.h

@@ -1591,11 +1591,12 @@ protected:
     // 0 = not dragging, 1 = drag just started, 2 = drag in progress
     unsigned char       m_dragStatus;
 
+#if WXWIN_COMPATIBILITY_3_0
+    // Unused variable.
     // 0 = margin, 1 = label, 2 = value.
     unsigned char       m_mouseSide;
 
     // True when editor control is focused.
-#if WXWIN_COMPATIBILITY_3_0
     unsigned char       m_editorFocused;
 #else
     bool                m_editorFocused;
@@ -1634,8 +1635,8 @@ protected:
     int                 m_clearThisMany;
 #endif
 
-    // Mouse is hovering over this column (index)
-    unsigned int        m_colHover;
+    // Mouse is hovering over this column (index), -1 for margin
+    int                 m_colHover;
 
     // pointer to property that has mouse hovering
     wxPGProperty*       m_propHover;