Addresses [MJ-957], [MJ-955], and [MJ-951]

Went with a minimalistic approach this time in an effort to avoid regressions. This addresses the off by one error observed in the PRM date widget, the AttributeError observed by clicking "View All" in the same widget, and the record filter regression caused by my previous attempts. 

Depending on how long this takes to review/merge, I'll probably do refactoring in a different PR to reduce code duplication.
This line is the main reason we don't need the exception clauses that I removed. Now we will only be dealing with non-empty strings and None types.