Problem

Inline Comment Popup such as the following does not show up for certain users, when a text is highlighted:

Diagnosis

1. Make sure that the user has the permission to add regular comments to the page
2. Make sure all the modules in the Confluence Inline Comments add-on is enabled ( Confluence Admin >> Manage Add-Ons >> All Add-Ons )

Cause

The Text Select feature is disabled in the User's configuration (Click on the user's Profile Picture on the top right corner, and hit Settings):

Resolution

Click on the user's Profile Picture on the top right corner, and hit Settings

Then hit Edit, and check on the Text Select checkbox. Then hit Submit.