Living: Sliding wardrobe door opens by itself [SOLVED]

Sliding wardrobe door opens by itself [SOLVED]
Image from Locky's English Playground

Back in January, my sliding wardrobe door had been refusing to close, opening by itself automatically. Tried climbing up to the top of the wardrobe and lying flat on the floor looking up to see if there were any broken parts, but still failed to see anything wrong with it. What I am certain of, is that there is no ghost doing this. It has to do with science.

Looking up, door is slightly tilted downwards on the right side
Image from Locky's English Playground

Took me a while to figure out what the issue really was. Apparently, it has to do with the weight of the sliding door (and gravity, if you like). 

Looking from the top, door is slightly tilted downwards on the right side. 
Using L-wrench to tighten the nut to relift the right side
Image from Locky's English Playground

Because the sliding wardrobe doors are made of heavy wood, the weight it exerts on the nuts and bolts is immense! Repeated use of the doors from pulling the door handle from left to right adds extra force to the nuts and bolts, causing the door to dip to the right side over time.

A graphical look of the sliding wardrobe doors (Blue arrow is the weight, red arrows are component forces)
Image from Locky's English Playground

This dip plus the weight of the door create a side-way force from left to right, making the door sliding open on its own. After tightening the nut from above the door, the problem was finally solved.

Now, at this point, I am thinking, why has no one ever linked the learning of free body diagram in Mathematics or Physics to realistic cases like this? This will give meanings to students as to why they have to learn resolving forces?