@User: You could also extend the existing key/button macros so that Shift-Button-1 emulates Button-2 or something like that.

that sounds helpful, any guidelines on how to achieve this?

There is a file (given the default installation location for magic) /usr/local/lib/magic/sys/.magicrc that has all the default key bindings (magic does not differentiate between keys and buttons, by the way). You can create a new macro file and source it from the .magicrc file in your project space using the Tcl command "source <file>". Macros can be redefined at any time. So you would just need to add a few like "macro Shift_Button1 "*bypass paint cursor" (or you can use Alt_ or map it to the "p" key or whatever works for you).

got it, some thing like sed -e ‘s/Control_Button2/Shift_Button1/’ then, thanks