Previously, when one activated the filter markup list tool, there were arrows next to the column headers to prompt users to click the column headers to filter the markups list. However, in Revu 21, the headers become greyed out when the filter tool is activated and they no longer have an arrow, and it looks as though the tool is broken if one is used to the previous UI. It is not intuitive, and I suggest a change to the UI to make it clearer that the headers of the columns in the markups list are clickable/ that's the next step to set up new filters.
