Application Locks Up on "Waiting for table metadata lock"

While working on table modifications in multiple instances of HeidiSQL, the application sometimes freezes when the TreeNav UI triggers a DB request dependent on the table metadata lock. Sometimes the application white-screens, other times it prompts the debug window (continue, close, restart). Perhaps the application should check for necessary locks before making the data request. Maybe create an option to check before nav, to limit overhead for those running single sessions.

What's exactly blocking *which* SQL command?

It's usually the "SHOW" commands that trigger when you click the DBs and Tables in the TreeNav...

And another instance is executing a command which blocks that SHOW command?

That's how it appears to occur. Of course as I'm typing this, I can't seem to duplicate the issue :)