Pasting issues with Gnome Calculator

[DynV Montrealer]

I've installed Gnome Calculator and I'm having a rather difficult time
pasting to it. I work on Notepad++ and when I'm ready to have a formula
calculated I paste it to GC. When trying to use Ctrl-V or Shift-Ins it very
rarely, if ever worked, it seems to past old formula, nothing in Windows
clipboard. It seems I very often, if not always, need to go through mouse
selection (of the text) then copying using the contextual menu then in
Gnome Calculator pasting using the mouse.

Is there a way to more easily paste in Gnome Calculator ?

Thank you kindly for your help