Embed window disappears in tab view

[2b-t]

Hey again,
I had the time to play around with your plug-in some more and it is indeed very handy. I have found though two small bugs (on Ubuntu 18.04 and ROS Melodic):

• When trying to switch to tab view inside rqt by pulling another rqt plugin onto the rqt_embed_window the embedded window disappears. Interestingly this does not happen instantly when doing it the other way around and puling the rqt_embed_window onto another rqt plugin but when switching to the other plugin and back to rqt_embed_window latter will disappear as well. In both cases the error message QXcbConnection: XCB error: 10 (BadAccess), sequence: 36179, resource id: 62914565, major code: 2 (ChangeWindowAttributes), minor code: 0 is displayed in console. When switching back to the side-by-side view everything works as intended again. Here a picture of what the bug looks like:

• On the screenshot can also be seen another weird behaviour: When executing several commands after another by clicking the configuration icon and inputting a new command to run, the plugin name will include all the previous commands. This persists also after restarting but I was able to reset it by clearing the configuration and plug-in settings with rosrun rqt_gui rqt_gui --clear-config.