@icon using glob:var cannot be parsed properly in DO13

In the buttons,

@icon:#ExternalCompare:BeyondCompare3,$glob:ExternalCompare+BeyondCompare4

"BeyondCompare4" after "+" will be treated as a variable,and then an error occurred:
because BeyondCompare4 is an unkown variable.
So as minus "-" , $glob:ExternalCompare-BeyondCompare4 reports error too.
I have to use underline “_” instead in DO13: $glob:ExternalCompare_BeyondCompare4

while in DO12, "ExternalCompare+BeyondCompare4" will be treated as whole variable.
sorry for my poor English!