I'm just describing what behavior is being exhibited in the sim.
The issue is, the log should have recorded you opening the menu and eventually the menu closing down with a choice, a timeout or even not closing down. Instead, is not even registering, you tried to open the menu in the first place.
And that is precisely why I'm quite sure your issue is related to Simconnect communication because, in order for GSX to register you opened the Toolbar menu, it requires GSX being able to read some variables set by the menu code, and they are read using standard Simconnect calls, so I can't see any reason, other than a problem with Simconnect itself for not being able to communicate.
It's not as if GSX is crashing it's just prevented from communicating with the sim or, at least, the part related to reading the variable the menu surely sets.
I don't believe its a sim object limit as some of the airports I'm seeing the issue occur at are small and without AI Traffic.
That's just the most common case, and the airport you are in doesn't really matter, because ALL AI counts towards the limit, that includes the ones in the "AI reality bubble", which is about 30 nm around the airport so, you might still have lots of AI counting towards the max Simobject limit, as long there's a busy airport close enough.
But again, the max Simobject limit is not the only reason why the communication might have stopped, another possible cause is another add-on sending too many commands through Simconnect that MSFS can't keep up with all of them so, a first test might be disabling every addon that is using Simconnect and leave GSX only, to verify this theory.