One thing I've noticed as I've used my wall hanging tool cabinet is that the doors have started to sag. The cabinet box is 3/4" birch plywood, and the doors include face moldings as decoration. That, and the fact that each door holds a full complement of tools means that the doors are very heavy. Even the full length piano hinges i used to attach each door to the frame are not enough to keep the doors vertical. Plus, I suspect that the weight may even bow out the sides of the box.
I had counted on the magnets mounted in the top frame would hold the doors vertical, but that has turned tou to not be enough. In fact, the right door has been sagging enough lately that I can't even get the magnet to engage the steel attach plate.
So I decided to make a mechanical fix. At least when the doors are closed, they need physical support. Thinking about this last week, I realized a block with a ramp on the top front would guide the top edges of each door to align with the top frame. And if I made the back edge of the slope on this support flatten out just before the door reaches fully closed, each door would settle onto a flat spot on the block. This would ensure that the doors are perfectly aligned and fully supported.
I picked a nice thick piece of silver maple, about 12/4 in thickness and about 5" x 5" on a side. Then I planed a slope into the front edge. Then I just mounted it to the bottom edge of the top of the case, positioned so the sloping porting sticks out about an inch. This I screwed to the case from the top with four sturdy 2" long screws. It worked like a charm. The doors are now sitting flush and there's a nice satisfying 'cachunk' when they close and the magnets engage.