i'll stand by my +1 of this request. whilst i appreciate that the left navigation panel can be docked or undocked with a single click, and that the drop down menu is also an option, both these options require navigating the mouse pointer to a very specific point. now, i know this is hardly a large issue, but i use MB on a laptop using the mousepad rather than an actual mouse which is obviously nowhere near as fast or precise to navigate with. the beauty of the way this feature works (for example) in lightroom, is that a brief nudge of the mouse ANYWHERE on the left edge of the screen activates the floating window (without resizing the main window and thus preserving limited space on a low resolution screen) for as long as the mouse pointer remains in the left portion of the screen.
in day to day use on my set-up the drop down menu or continually docking or undocking the panel does not feel workable and my current solution is to continually leave one tab open with the left panel open for navigation but then to spend most my MB time in other tabs with it collapsed.
anyway, this is hardly a big issue but thought i would share my 2 cents...