I found an irritating minor issue in creating custom filters. What I did:
selecting menu item "Custom Filters"
giving the new (filter) a name; adding some filter attributes
saving the newly created filter
(back in seeing "current filters")
selecting one another of the "current filters"; selecting "edit"
FIlter name has the content of the previously created new filter
Statement seems to be having the content of the filter I wanted to edit.
Don't know what happens, when saving this; if this maybe destroys one of the filters. Please check