Message Log window broken in DRC

[whitis]

The message log window will not scroll when running DRC.
The [CANCEL][OK] dialog box apparently breaks event
handling for the message log. This is a really bad
time for scrolling to be broken. For example, you
want to scroll back to see what the rules were.
IIRC, this is a change from significantly older
versions of PCB.

Also, the message log fails to pop to the front. A
bunch of textless ("Press OK to continue DRC checking"
doesn't count) OK dialogs is quite confusing. Putting
the text in both the dialog and the message log would
be a good idea.

PCB Version: 20060422

[Felix Ruoff (felixruoff)]

I can confirm this bug. Seems, that DRC blocks many/every pcb actions. Tested with git head

[Nicklas Karlsson (nicklas-karlsson17)]

I could confirm message log will not scroll while running but then DRC check is done it will scroll again. This should be OK if pcb is single threaded.

[Chad Parker (parker-charles)]

This occurs because the DRC runs in the main thread.

Because the DRC actually changes the state of the data during the DRC check (e.g. lines change size, flags are modified) we cannot allow the user to interact with the layout while it is running.

I think the simplest solution to this problem is to create a dialog while the DRC is running that indicates which test is being run and how much time has elapsed. This essentially tells the user "hey, I'm busy doing this work right now, come back when I'm done".