Updated to 16.13
It is now drawn as expected most of the time.
There is still an issue if the button is hidden, then changed to a split button and then shown.
I am seeing a significant performance issue.
I have an application. When I select an item in a tree view it builds a panel to show details based on properties of the associated object.
In one example this produces a panel with 5 edit boxes, 4 check boxes 10 labels and 4 buttons.
With 16.12 clicking on an item resulted in the form appearing immediately. There is a flicker as the previous panel disappears and is replaced.
With 16.13 there is a blank view for 4 or 5 seconds before the new panel appears.
In another case the panel has 3 edit boxes, 4 labels and 1 button and it is very much quicker but it is still a second or so.
Note this application isn’t skinned but the control it uses to build the panel uses skinned components.