Pull-requests: Undo the "File has been viewed" operation.

When doing the code review in the pull-request I see on the left the tree of the files that are about to be changed by the current pull-request. The files names (in the file tree) are shown with the bold font. 

1. When I click the file name the font changes from bold to plain (showing that I have viewed the file). I want to be able to undo that change, I want to be able to make the file name displayed (in the file tree) with the bold font again.
2. Let's say there are 2 file names (A and B) are displayed in the left panel (file tree) of the pull-request. I click file A (file name A changes from bold to plain, but file name B stays bold) and in the source of file A I see that a new variable is being added to file A. I want to see how that variable is used throughout the current pull-request. I enter the name of that variable into the search box right above the file tree and press enter. It shows me the search results instead of the file tree. If I click the occurrence of the variable in the file B (which should still be bold in the file tree) then it displays the contents of the file B and shows (with yellow background) the variable searched. THen I cancel the search by pressing the cross on the right inside of the search box. It displays the file tree again (instead of the search results) but now the file name B is displayed in plaint font instead of bold font, but I want it to be still displayed in bold font (despite the fact that I viewed the file contents while analyzing the search results).

Item 2 is more important for me than item 1.