Sorry not sure if bugs belong here but hopefully someone will see it. The gist of this problem is, say you had sent orders to attack a territory, but later you decide not to and you decide not even to deploy any troops there reducing the territory to 0. In the attacking orders, if you want to reduce it back to 0, you have to type in 0 instead of using the scroll bar. This is annoying and slows down the game.
In this example, I (red team) was attacking the 21 territory with 17 troops, but decide to not and I decide not to deploy the 17 there, reducing it to 0. To get rid of the attack, I clicked on it but the only way was to manually typing in 0 which is annoying. I would prefer to scroll it down.
https://imgur.com/a/kwUE99P