I'm using Firefox 3.6 and Last Tab 2.2, when I press Ctrl-W and then without letting off the control key, press Ctrl-tab, the last tab plugin is disabled. After this the tab order reverts to linear and no tab selection popup is shown. Firefox still shows the plugin as enabled in the Tools -> Add ons menu.
Stephen
edit: platform is Windows XP SP 3
Okay, I can confirm this happens. This is a bug with LastTab and related to how it tracks tabs. Given the uncommon conditions necessary to trigger this I'm not going to expend a lot of effort to fix it in LastTab 2.x; I will ensure it won't happen in the 3.x series.
Does LastTab work after you release the control key and try again?
In order to better work with other control key based tab navigation methods, such as say control-<digit>, LastTab temporarily disables tracking the active tab until the control key is released. The keyboard sequence you mention isn't exactly standard behavior: control-w, tab, tab, etc. Nevertheless control-w results in the active tab changing and so LastTab stops its tracking. Normally the control key would be released right after pressing control-w so the behavior you see would never happen.