wxSize wxGenericTreeCtrl::DoGetBestSize() const
{
+ // make sure all positions are calculated as normally this only done during
+ // idle time but we need them for base class DoGetBestSize() to return the
+ // correct result
+ wxConstCast(this, wxGenericTreeCtrl)->CalculatePositions();
+
wxSize size = wxTreeCtrlBase::DoGetBestSize();
// there seems to be an implicit extra border around the items, although
// scrollbars appear in a tree with default/best size
size.IncBy(4, 4);
- // avoid caching (necessarily arbitrary) default size for empty tree
- if ( GetRootItem().IsOk() )
- CacheBestSize(size);
+ // and the border has to be rounded up to a multiple of PIXELS_PER_UNIT or
+ // scrollbars still appear
+ const wxSize& borderSize = GetWindowBorderSize();
+
+ int dx = (size.x - borderSize.x) % PIXELS_PER_UNIT;
+ if ( dx )
+ size.x += PIXELS_PER_UNIT - dx;
+ int dy = (size.y - borderSize.y) % PIXELS_PER_UNIT;
+ if ( dy )
+ size.y += PIXELS_PER_UNIT - dy;
+
+ // we need to update the cache too as the base class cached its own value
+ CacheBestSize(size);
return size;
}