Thanks. I created a patch from the differences to the trunk file and uploaded it to the bugtracker report. I also uploaded a demo. It shows me that the repaint issue after setting the csSimple combobox height by code is not yet solved.
While I normally use trunk I played with the demo with Laz 2.08 to have an unmodified system and to see the original painting bug again. Are you sure that disabling the integral height feature of the listbox really is the solution? I get the feeing that it simply hides the original repainting issue of the stationary listbox. Wouldn't it be better to find the handle of the stationary listbox and send a redraw message (or similar, of course)? Did you ever play with the handle of that listbox? I think it is accessible via the TComboboxInfo (TComboboxInfo.hwndList) - see ComboboxWndProc(): Win32Extra.GetComboBoxInfo(Window, @Info)
Another rather elemental problem: I don't know about the strategy what the LCL does with a control that has extended possibilities in one widgetset compared to others. Does it implement the full feature set in that widgetset and leave the fissing feature unimplemented in the others? Or does it implement only the "common denominator", i.e. only what is common to all, so that the control behaves the same in all widgetsets? I think I'll have to ask the other developers about it.