Till now keyboard shortcut for Firefox Panorama aka Tab Candy is Ctrl +Space is for Windows and option+space on Mac and now it has been changed and newly assigned one is Ctrl +E for Windows and cmd+E on Mac.

Firefox Panorama keyboard shortcut

Aza Raskin tweeted in Twitter saying that “Due to IME incompatibilities we are changing Firefox Panorama Keyboard shortcut to cmd/ctrl-e http://bugzil.la/592183

Old shortcut still works for Users using previous versions of Firefox 4 beta, however new shortcut will activate Panorama in latest Firefox 4 nightly builds and in upcoming Firefox 4 beta 7.

Firefox Panorama keyboard shortcut

Ctrl +E for Windows

Cmd +E on Mac.

Update : Mozilla changed Panorama shortcut yet again its Ctrl+Shift+E now,

Read Panorama Shortcut Changed Yet Again, It is Ctrl+Shift+E Now