Thanks Erel for CTRL+A suggestion.
If you have I nice way for shift +_mouseclick, I look forward to read it.
Underneath, I will try the shift + click selection as follow:
First storing the start-rowid in a var, at row click without shift pressed.
After keyboard shift + mouse click storing the end-rowid.
At that point I do have a start and end in a range of rowids / lines
In a for-next I can select each row in that range.
Most difficult will be detect the shift+mouseclick.
Maybe this post will be helpfull for me.
https://www.b4x.com/android/forum/threads/b4xtable-keyboard-navigation.135625/
If I have any good results , I will post it here.