Minecraft inventory when shift and drag mouse won't put items into other inventory

Well if you're trying to spread items equally in a chest then I'm pretty sure you need to press the scroll wheel, not the right mouse button.

Shift + Left Click items individually is to quick-transfer. What you're describing is a feature of Inventory Tweaks, but is usually done with the Left mouse button (whatever Button 1 is assigned to).

Shift + Right Click + Drag with an item already grabbed quick-places one item per slot hovered over. Shift + Left Click + Drag does the same, but has the stacks equally spread out, with the remainder staying in hand.

There is also a known bug prior to 1.14 where in certain cases, losing focus of the window breaks all UI events in inventories until you restarted Minecraft.