Well actually there is and it's rather simple.
I have no idea whether it is unique to my system but let me explain. I have an alternative foreign language keyboard set up on my Windows 7 (64bit) operating system. To switch between english and greek I must hit ALt & Shift together in unison. If I do this in Lightroom, & it is always by mistake, then all of the lightroom shortcuts are disabled.
The Thread that Came Back from the Dead. (I'd insert a smiley here, but I don't like smileys, either.)
Anyway, that's a Microsoft-specific keyboard mapping command that is designed, as you point out, to allow the user to quickly toggle between two different languages. Another kind of shortcut
, if you will. There are equivalent commands on OS X and for some Linux window managers, but this is happening at the system
level, not in the application. Presumably the fact that it disables the Lightroom shortcuts on your system is an unintended side-effect. Just a conjecture, but maybe LR doesn't grok Greek.