STR: * Cold start Fennec. * Open the Settings page by clicking on the three vertical dots. What happens: First of all the menu which comes up by clicking the three vertical dots, some of the entries in them get activated/clickable after some time (and this time duration is observable). When the Settings option is activated, click on it. The Settings page opens quite slowly (again the page opens with links disable and then the links get enabled). I'm on the Nexus 5 with the latest stock Android version (4.4.4). I know showing the options first and and then enabling them is an optimization in itself, but this is still a slow and laggy experience. Compared to Chrome, where the Settings page opens quite quickly on the same phone. I think we can optimize things a bit here.
We rely on having Gecko initialize before settings is usable hence why you see the items greyed out. I don't think there's anything that can be done here.
It wouldn't be impossible to show the top-level settings menu prior to Gecko load. We just don't, because getting it right isn't trivial, and so it hasn't been a priority. Settings probably needs to become more sophisticated to handle some of the smart summary lines we want -- "Syncing firstname.lastname@example.org", for example -- and with that could come delayed-enable, not just delayed-status. This isn't something we don't want to fix, and it's not a stretch to imagine us doing it, so let's keep this open.