I dislike the change that now that menu button is no longer right aligned. But I also cannot configure that button in any way. I can not hide its text, I cannot change its icon to a wrench. Neither right clicking it provides an option, nor does it appear in the Configure Toolbar dialog. Reproducible: Always
So what do I need to implement that this bug can be set to RESOLVED? Is it sufficient for you the edit the text + icon with a context-menu? Or must it be part of the Configure Toolbar dialog? In the longterm I'd anyhow prefer a global KDE solution in KWin to have a menu-button in the window-titlebar like e.g. Firefox has. I think Martin Gräßlin has blogged about this some time ago...
You can now configure the icon/hide the text again. Closing this report.