The hotkey "Ctrl + A" selects all segments, but doesn't appear in Configure Keyboard Shortcuts. As a result, Configure Keyboard Shortcuts allows "Ctrl + A" to be assigned to another function.
Even when it's "remapped" in CKS, "Ctrl + A" continues to select all.
Either "select all" should appear as an entry in Configure Keyboard Shortcuts, or CKS should not allow assigning "Ctrl + A" (and any other baked-in hotkeys).
It turns out the "space" hotkey is similar to "Ctrl + A".
Configure Keyboard Shortcuts doesn't realize "space" has built-in roles, which are either stopping a running action like wiggle, or deselecting all if no action is running.
Configure Keyboard Shortcuts allows "space" to be remapped, but thinks it's already mapped to something called "Copy from guide!". I have no idea what "Copy from guide!" is, and it doesn't appear in the CKS list. (I added a guide, and there's still nothing.)
The bogus CKS assignment has no effect on what "space" does in Foldit.
"Space" should probably in the protected class along with "Ctrl + A".
Interestingly, "ACTION_COPY_FROM_GUIDE" shows up in hotkeys.txt after its hotkey has been hotwired:
"ACTIONS_REMOVE_BANDS" : "Space"
"ACTION_COPY_FROM_GUIDE" : ""
I haven't seen an empty hotkey ("") in hotkeys.txt before, at least not in this version of Foldit.