Are there any chances in H9 on Lynux to keep Parameter Ladder functionality and in the same time be able to paste text into text parameter field using MMB ? Is this customizable somehow ? Maybe it is possible to set some keyboard hotkey in addition to MMB action in case one needs to past text instead of ajusting some numbers in expression for example.

You can only MMB to paste in the textport, Edit Comments or dialogs for editing text. This works for Windows & Linux.

For parameters, you have to use Ctrl+c as the MMB is for the ladder.

Cheers!
steven