Just spent close to an hour doing a ‘binary search’ to figure out which extension was killing ctrl-c, keeping me from using it to copy text from various windows in WME.
I see that is is a known characteristic of magic-wand. Documented in
https://www.waze.com/forum/search.php?keywords=ctrl-c&t=118064&sf=msgonly
Might I suggest that it may be a good idea to change that default takeover of shortcut keys so that the common windows ‘copy’ shortcut is no longer preempted by Magic-Wand when it is installed?
Perhaps alt-c or ctrl-shift-c would be less ‘intrusive’ !
I strongly suggest that all script writers avoid preempting the most commonly used editing keystroke shortcuts (ctrl-c,ctrl-v, ctrl-x and ctrl-s … and perhaps some others that slip my mind at this moment.)
I see that the ‘code’ // Hotkeys
registerKeyShortcut("WMEMagicWand_CloneLandmark", "Clone Landmark", cloneLandmark, {"C+c": "WMEMagicWand_CloneLandmark"});
registerKeyShortcut("WMEMagicWand_OrthogonalizeLandmark", "Orthogonalize Landmark", Orthogonalize, {"C+x": "WMEMagicWand_OrthogonalizeLandmark"});
registerKeyShortcut("WMEMagicWand_SimplifyLandmark", "Simplify Landmark", simplifySelectedLandmark, {"C+j": "WMEMagicWand_SimplifyLandmark"});
registerKeyShortcut("WMEMagicWand_HighlightLandmark", "Highlight Landmarks", highlightLandmarks, {"C+k": "WMEMagicWand_HighlightLandmark"});
in the script seems to preempt ctrl-c and ctrl-x.
I do appreciate all the work that went into writing the script. I haven’t had a chance to play with it, just installed it a few days ago with the intention of testing it, when time and opportunity presented itself and part of ‘time’ has been spent fighting and cursing the broken ctrl-c 
Additional hint to anyone else having the problem: I just modified those lines by adding “//” at the beginning of them (effectively commenting out the registration of those shortcuts) and that ‘fixed’ the problem I have been fighting for days. 
I can also now state that it takes close to an hour to do a binary search to narrow down the culprit when you have over 80 scripts installed. 
PS: tried MagicWand a couple of times, After several times of being unable to find anything, something locks up WME and I have to kill the tab and restart. Maybe I broke something by adding the “//” to comment out those line. I’ll give it another try when I have some spare time. For now, it is disabled in Tampermonkey.