Issue with autohide toolbar at bottom

I've a button opening a toolbar with autohide. On first button-press no toolbar appears, when pressing again one appears fixed between bottom of DO and above taskbar, and a second one is shown on the taskbar and autohiding. What I'm doing wrong?

Button:

Toolbar NAME=_Aimp FLOAT=autohide,toplevel,transparent

Screenshot:

I think Windows has issues with autohide toolbars on the same edge as the taskbar. I would avoid that configuration.

But the toolbar originally was placed centered and above the taskbar (using POS).

Autohide toolbars have to be docked to a screen edge.

Ok, didn't know that (using floating toolbars for the first time).