How does configuration node change detection work

Hello, I'm quite new to node red developement and would be glad to get some help to this situation:
My configuration node has six input fields. Each input can have a select next to it that is created / deleted dynamicly (if there is a defined set of values). In this case I set the input type to hidden and create a select.
Inputs ids are node-input-param0 ... node-input-param5, select ids node-input-param0_select ... node-input-param5_select
In oneditsave I iterate over the inputs, check if there is a select nextby, compare the values and set the input value to select value if they differ. But even if I don't change anything and close the configuration node it is marked as changed.
Any suggestions?