The "Add filter" button is disabled when the Value is set to 0. Probably because zero is falsy in Typescript and there is an "if value" statement somewhere that should be "if value == null"
TL;DR
The "Add filter" button is disabled when the value is set to 0. This is because zero is considered falsy in Typescript. A possible solution is to update the code to check for "null" instead of "if value" in order for the button to be enabled. There is an ongoing discussion on GitHub regarding this issue.