Crispy,
Are the drawers full too? If not, your cart could be top heavy and unstable when moved.
Another thought. I may be strange, but I like to keep the top till of my cart pretty open (i.e. go-to screwdrivers, a few smallish prybars and two rails of metric sockets. The till is where I work on things.
Also, I like to keep the overall tool complement to a bare minimum; nothing but go-to, absolutely essential, tools.
The bottom tray is pretty much liquids (grease & grease gun, brake fluid, motor oil, atf, w/w fluid, coolant, and a few spray cans assorted cleaners & penetrants).
This strategy keeps my cart easily mobile and very stable.
Of course, everybody has different cart strategies.