Across multiple versions of Red Hat (now 7.4) and Thunderbird (now 52.3.0, 64 bit), I occasionally experience a malformed dbus notification for an email received in Thunderbird that includes a calendar entry. When this occurs the dbus notification is blank and permanent (ie. it doesn't disappear as it should after a few seconds). Also, the Thunderbird pop-up that asks if a notification of your response to the new calendar entry appears *behind* the dbus pop-up, which is in the lower right-hand corner of my primary monitor (ie. the pop-up loses the context of the main application window in terms of the alignment on the desktop). Under my current OS and software installation, I'm able to drop the Thunderbird pop-up out from behind the dbus pop-up and respond successfully to it. However, the dbus pop-up never clears. The only reliable solution to recovering the ability to see the affected portion of the desktop is to kill the thunderbird process. Note that quitting the application is not enough. This suggests to me that there is Thunderbird dimension to the problem, though perhaps there's also a dbus dimension to it as well. This issue only happens a fraction of the times that I receive calendar notifications via emails in Thunderbird, so it may be related to the timing of me clicking on the "add to calendar" button relative to the interaction with dbus behind the scenes.