LOL... mine never leh... I have no bookmarks toolbar. You right
click on that area again, make sure the Bookmarks Toolbar is not
ticked. If you have other toolbars, it will show up as well, which
probably explain why it always shows up.
Just maximize it, close Firefox and start again. It will be
maximized. Otherwise, change something with Firefox's
shortcut.
Right click on Firefox's shortcut and select Properties.
Select the Shortcut tab.
Under Run, select Maximized from the drop-down list.
Click OK.
Start Firefox again.