This is a pain in my neck also…
I wrote about this in the Z4 wishlist but it did not make it to Z4.
The problem is disappearing UI icons while working in different modes.
For example…
If you are working with a Polymesh 3d mesh, the Texture,Displace
and Normal Map menus are visible but if you are working with 2.5d paint tools they are not.
This causes a problem when saving custom UI elements.
The workaround i use is to create a custom UI for working with 3d meshes
and a seperate custom UI for working with 2.5d painting tools.
I can’t count the number of times i have saved over my custom UI
at the wrong time destroying my UI.
Seems like it would be easy to fix this by making all icons/menus remain
visible at all times.