What happens: When loading a tab group that has several tabs, the UI becomes unresponsive. To reproduce: 1) Create a tab group with at least 10 bookmarks 2) Go to the Bookmark menu and load that tab group 3) Watch a partially drawn bookmark-menu remain on the screen while all the tabs load. What should happen: The loading of tabs should be given lower priority than rendering the UI. Perhaps the first tab loaded should be given higher priority so that the page the user is looking at gets loaded first.

Related: bug 141615

The UI is unresponsive because it's XUL, and not the fastest UI kit in the world (YET!). Once all the tab and browser-objects are created, the UI becomes responsive, and you only have to wait for the sites to appear. Your other concern, that the first tab should be prioritized, is covered in bug 141615. *** This bug has been marked as a duplicate of 141615 ***

marking verified as a duplicate. if you decide to reopen this bug, please clarify why. search string for bugspam removal: SalviaGuaranitica