Avoid refreshing not currently visible items in generic wxListCtrl.

This is useless at best and resulted in GTK+ warnings because we ended up
(somehow -- is there another bug lurking here?) with negative items height in
this case.

Closes #16862.

docs/changes.txt

@@ -597,6 +597,7 @@ wxGTK:
   target window.
 - Fix crashes in wxGTK3 when running with non-X11 backend (Marco Trevisan).
 - Fix coordinates of wxSetCursorEvent propagated to parent windows.
+- Fix GTK+ warnings when refreshing wxListCtrl items (Scott Talbert).
 
 wxMSW:
 

src/generic/listctrl.cpp

@@ -1935,6 +1935,13 @@ void wxListMainWindow::RefreshLines( size_t lineFrom, size_t lineTo )
         size_t visibleFrom, visibleTo;
         GetVisibleLinesRange(&visibleFrom, &visibleTo);
 
+        if ( lineFrom > visibleTo || lineTo < visibleFrom )
+        {
+            // None of these lines are currently visible at all, don't bother
+            // doing anything.
+            return;
+        }
+
         if ( lineFrom < visibleFrom )
             lineFrom = visibleFrom;
         if ( lineTo > visibleTo )