1

Add option to place show desktop button on titlebar, such like close, minimize, maximize, help, etc.
This will allow to fast desktop access, without using a keyboard and allow to remove all panels.

Why? Because central place of desktop should be plasma. User might place very useful plasmoid on it, if we allow to fast access to it.

Also, allow to turn option: show 1px line. If user click on this 1px line on bottom, plasma desktop will be displayed.

Also, instead of adding new button, it action for right click on minimize could be show desktop.