Comboboxes in csSimple will not size in the designer and leaves trailing unpainted areas in the drop down list.

Original Reporter info from Mantis: jamie @jamie

• Reporter name: jamie philbrook

Description:

First, I can randomly get to size the csSimple combobox at design time. it seems this is random but when it does work it will work for the remainder of the session until I restart laz. After that , 90% of the time I can not expand the height of the edit box to show the list box which is a static viewable list box in csSimple mode..

At runtime I can force the control to show the list but I've also noticed there is a window behind it that is taller than the actual combobox coming from the OS. If you put a csSimple on a form with its list showing and then cover it via a form resize and then reshow it, you can observe the region that does not get covered by the OS part of the combobox. This region belongs to the Combobox control because it receives mouse messages.

Steps to reproduce:

Drop a csSimple on a form, expand it to shows its list box if you can, if not, do it at runtime and you can see the list box then by setting the height property of the control

Drag the form size small enough to cover the control and then drag it back open again, you will see there is two controls there, a windows in the back and the actual ComboBox from the OS, they don't match their heights.

I have played with the Height property and I can get a perfect multiple where it will not show this band of black so there Is an issue obviously in the Widget.. (Win32/Win64);

Please take a look at this, to problem seems to be widget related and looks to be like it was custom created..

All of this works perfectly fine in my Old Delphi and current Delphi 10.x

Mantis conversion info:

• Mantis ID: 37129
• Version: 2.0.8
• Fixed in revision: 63251 (#102cb0b3)
• Target version: 2.0.10