vb6 MDI app - when mdi form maximized

I am working on an old visual basic 6 app, which has just developed an issue since adding a ribbon bar, It never used to have.

It is an MDI form application, which has 1 main window which has a menu at the top and status bar at the bottom, along with 2 other status like bars. It also has around 50 Child windows to go within this master frame.

When the user maximizes any child window it seems the window maximizes but does not notice the toolbars at the bottom and it maximizes below them (out of view), so the bottom of the child window does not meet up with the top of the toolbars.

I have done 4 pictures which show it is design time, runtime normal and then maximized, as you can see it hides the buttons.

I have never seen this before

I have tried to code some resizing logic to counteract this in the child Private Sub Form_Resize() event, however, it has no effect at all.

Which leaves me to believe the window resizing when maximizing is dealt with via the windows system itself, or buried deep in vb, where I can not change it.

I have also tried bringing the controls to the front, then back etc, no impact

I have tried changing the zindex around in all ways, no impact

Has everyone ever seen this before or have any ideas

Thank You for reading, any help would be greatly appreciated

Thanks