While I’m not sure without looking at the source, I suspect the shortcut keys are hard coded and thus need a code change. Someone else may know a trick though.
That is one option (and the usual suggestion in Fritzing), but if you want breadboard for a tutorial for instance and would really like to show the probes, it is easy enough for me to make a custom part that illustrates test probes (it is a cosmetic change in the breadboard svg file of a two pin header). A couple of us made a ph probe for someone that wanted to do just that and this would be easier (parts making is fairly complex, so it is likely easier for me to do it than you).
Unfortunately my first guess is data base corruption due to a connection error that wasn’t reversible. If you post the sketch (the .fzz file, via the 7th icon from the left on the reply menu) I’ll have a look and see if I can fix it. One thing I see is unless the yellow square is covering a character, r11 and r12 have the same label and will cause a short.
Since it really is fairly trivial to make a new part, here is a part for a pair of test probes more or less life size in breadboard (about 4 inches long). To load it, download the .fzpz file, then in Fritzing file->open , navigate to where the .fzpz file is select it and click ok. The new part will appear in yout mine parts bin ready for use. The connections in breadboard are on the end of the lead wires where they would plug in to the meter (I was too lazy to put banana jacks on the end ).
test-probes.fzpz (4.8 KB)