The issue with "Fit toolbars" and "Optimize toolbars" should be fixed in trunk (r10566).
To get back the missing dropdown (if it is enabled), it should be enough to call one of these functions.
Elements inside a toolbar, that are not completely inside the mainframe, seem to be hidden with wx3.0 (at least with wxGTK).
The call to GetSize() used in FitToolbars() and OptimizeTooolbars() only returns the visible size, bot the overall size of the overall size of the window, GetBestSize() gives correct results.
And the gripper size has to be taken into account, otherwise parts of the most right toolbar might be hidden and therefore some elements not shown.