Dimension Limited Functionality Window
The Basic (free) version Dimension has limited functionality. It allows you to view plans and take measurements - but not save them. The next level up (Pro) offers considerably more functionality.
By special arrangement with Dodge Data & Analytics, the Basic version of Dimension is boosted to Pro functionality when working with drawings provided by Dodge Data & Analytics (Dodge drawings).
If you use Dimension to view Dodge drawings then subsequently view non-Dodge drawings, the loss of functionality may be confusing. To avoid this confusion, Dimension leaves the Pro functionality menus and toolbar buttons enabled. But when you use one, it displays the Limited Functionality Window rather than invoke the functionality..
To avoid this window, select "Admin/User Preferences..." from the main menu, go to the "Hints" tab and UN-check "Show hint window for limited functionality". Then Pro functionality menus and toolbar buttons will be disabled when working with non-Dodge drawings.