pyFormex provides easy access to scene manipulation functions (rotation, translation, scaling) by its default mouse bindings.
In pick mode however, the left/right mouse buttons without modifier key are bound to the selection/end_selection functions. The manipulation functions are still available when using the ALT modifier key together with the mouse buttons. However, many modern window managers bind the ALT+mouse buttons to some window manager operation, making simple scene manipulation unavailable during picking operations.

I propose therefore to change the default mouse bindings during picking operations in a way that manipulation remains available. I see three possible ways to accomplish this:

1. Use a different modifier key for manipulation during pick mode. Problem: which one? SHIFT, CTRL are taken. R-SHIFT, R-CTRL, ALT-G, WINDOW ? Might not always be available, might not be modifiers, might be taken for something else?

2. Keep the unmodified mouse bindings during picking operations. We then lose one of the bindings in picking mode: set, add, remove selection. I think this is no major problem, because in most cases the initial selection is empty, so set and add work the same. It could probably hinder to always have to push the SHIFT key while making a selection, but you already have to do that most of the time anyways, while adding to your selection.

3. Provide a key for switching between manipulation and picking mouse bindings.

A fourth solution would obviously be to change the mouse bindings of the window manager (wich is what I have been doing until now), but this requires more effort in explaining users how to do that. Moreover, users may never ask and assume that manipulation during picking is not possible in pyFormex.

What is your preference?