There is one bug, few couple suggestions
1) Rename "Conditions" tab to "Row Filter"
2) Rename "Mask" tab "Column Masking"
3) When somebody clicks "add" in conditions, the resource only applies to tables and views not columns. So, the the pick list should be on tables
4) change the text on the this pop-up box, it says "Add Column Row-based security", that makes no sense to me. Say "Row based security through filtering", in description say "Provide any boolean based criteria (ex:...)"
5) On masking "add" dialog, change

• target column ==> Column to Mask
• Masking ==> Column Expression

You can have hint in the bottom saying that, "Column Expression will be used in place of masked column in executed query"