increase vertical size of control in front panel

[EKoch]

This is an old discussion, but my problem is similar.

I would like to increase the width of the selection field on the right (only the part with the arrow) because it is not easily hit on a touch screen.

Control with diffent size, but field on the right does not change width.

I tried with "Costomize Control" but I cannot devide the control in different parts.

Any help?

Best regards