When there is a popup in new window and you close "main" window(where you have gazzilion tabs) first and later popup window, all remembered tabs are gone with next opera opening(opera opens with url of this stupid popup only)!!! this is so stupid and annoying !!
Do some property "isMainWindow" or make it so that it opens all windows with popup.

i have four workspaces with many tabs not closed intentionaly for months and then this happends....