In creative mode, you used to be able to clear up your entire inventory by clicking the red "X" from the down-right corner (The "Destroy item") while holding "shift". Now nothing happens.

It is mostly frustrating when building and just wanting to get rid of all that mess of blocks.

This issue occurs both in the 24w36a and the 24w37a snapshots

This feature does indeed work in previous snapshots such as 24w35a or 24w34a.