Applying the fix for that bug seems to mitigate this bug a little, although it doesn't totally fix it. I still get this bug intermittently, but it *seems* to be less frequent.
The fix is: Edit > Preferences > Advanced > General > Config Editor. Search for mail.compose.max_recycled_windows, double click it, and change the '1' to '0' in the 'Enter integer value' window that pops up.
Andrew, do you see this bug in both Firefox and Thunderbird?
If, like me, you see it more frequently in Thunderbird, the following might help. I was also hit by this (unrelated?) bug in the upgrade. https:/ /bugzilla. mozilla. org/show_ bug.cgi? id=917027
Applying the fix for that bug seems to mitigate this bug a little, although it doesn't totally fix it. I still get this bug intermittently, but it *seems* to be less frequent.
The fix is: Edit > Preferences > Advanced > General > Config Editor. Search for mail.compose. max_recycled_ windows, double click it, and change the '1' to '0' in the 'Enter integer value' window that pops up.