QtCreator looses pane configuration

I prefer to configure my panes for the debugger in the following way: I move the Locals and the Expressions over to the Breakpoints pane to create three tabs there, and partition the space about equally between the stack trace on the left and the stack of three tabs with Locals, Breakpoints and Expressions on the right. That used to work fine. 

Recently, QtCreator has started to forget the layout. It will make the stack of tabs very narrow each time I start a debugging session, or even just move the panes back to the original position after which I then have to enable the title bars, move the panes back where I want them, and then disable the title bars again. 

This is very annoying. 

I do not know if it also impacts other panes.