No, I said that I can't.

Yeah I notice that, I was running whit my M4 and I press 6 for my compass, and my character stopped instead of running and swap item.

Ahahaahahaahahah it's funny xD

It's for the lag

Yea, same thing, I jumped off and I died losing all my stuff :(

When you press "Use Ladder" the character will approach the ladder but instead of walk near the ladder, he make a long jump.
(Sorry for bad english)

Yes, same thing to me.

It's also happened to me, you can't use something is on the ground

Yes, same thing to me, I was at the airfield whit good stuff and I died losing all for this bug :(

Yes, it happened to me too.
It's funny, my friend was upstairs and I saw a door opening by itself ahahahaha

Yea it's useful

Yea, It's a feature. Example:
You have a canteen water in your pants and in your hotbar. You find new, better, pants. So you switch pants and you take the canteen from the old to the new one.
The canteen is still in the hotbar, and you don't have to reset that.
Understood?

It's not a bug, if you watch the item is white in the hotbar. This means that you don't have the item in your inventory.
You can drag an item in the hotbar away for clear that slot.

I think I know how to don't make this happens: you don't have to have a weapon/fists ready to shoot/punch. Press SPACE for lower the weapon/fists

Yep, same thing happened to me. I died losing all my stuff :(