My suggestion is that when someone runs out of a certain block in their hotbar and if they have the same exact block in their inventory that the block would transfer to the hot bar. (If this is confusing then here is another definition)
When someone is building.
And they run out of a certin block in their hotbar
But they have the same exact block in their inventory
Then that block would transfer into their hotbar.
(Hope that was a litttle less confusing)
Example:
I'm building with oak wood planks and then I run out of it in my hot bar.
But I have some in my inventory. The oak wood planks would transfer into my hotbar to where the oak wood planks I used were.

Thank You for Reading my Suggestion!
Please Comment.

 

Pretty sure the client side mod Too Many Items does this: so if you're desperate for this, it's available.
I don't really know much about mods though.
I wouldn't object to this being added as a general tool, so a vague support, I suppose?

 

Thank you for this information!

 

Support if possible

 

Thanks!

 

No support, Sorry

Some players like I would probably find this annoying when trying to do, such as, measuring distances, building stuff to certain sizes.

Like Lycel said, If you are desperate for this, just install "Inventory Tweaks"

 

There's a mod out there so you might as well download it, and if I'm honest, I want to be playing it vanilla. Lots of stuff aren't vanilla so we don't need more, no support.

 

Since you can just do this with mods, I don’t really think we should add it to the server. No support.

 

inventorytweaks does just this. no support.

 

Thank you for your opinion!

Thank you for your advice!

I respect your opinion.

Thank you for your commentary.

Thanks for spending the time to type this!