Is your feature request related to a problem? Please describe.
"Empty" button is very close to crafting result slot and Equip/Unequip button and sometimes misclicking leads to unintentioal clearing of the tanks.

Describe the solution you'd like
Having Empty Tank buttons a bit higher somewhere in the middle between bucket slot and crafting result slot would be nice.

Describe alternatives you've considered
As an alternative it could ask for confirmation

Empty tank buttons will be removed, instead player has to hold shift and click on tank to drain fluid

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack