Remember docked sidebar state when starting Opera
I use Messenger in the docked sidebar - I can change its visibility by clicking on Messenger icon which I do anytime I need and it feels very useful for me (I don't like default "floating" mode, because I can't use Messenger and browse websites simultaneously).
However, when I start Opera or just open new window, Messenger always pops up when I use this docked mode, even if I closed it manually in previous session / underlying window. Sometimes it leads to funny situations when I open the browser only to show someone some information and then huge Messenger bar appears and everyone who sits next to me can read my conversations.
It would be great to have an option "show docked sidebar at startup by default" to control it, or just remember previous state (opened/closed) of the sidebar.