Holding Alt and Double Clicking an item in the Viewport breaks cursor functionality.
When holding Alt and double clicking an item in the viewport, the selection icon turns into a double arrow icon and you can no longer select or move things in the viewport.
When holding Alt and double clicking an item in the Scene Window, the Attribute Editor clears out as expected.
Steps to reproduce
Step 1: Open a new scene. Step 2: Press Alt + Rectangle Tool to create a rectangle in the viewport with default settings. Step 3: Hold Alt and with the LMB, double click on the rectangle.
What is the current issue's behavior?
It locks the functionality of the cursor and you can no longer select or manipulate items in the viewport.
What is the expected correct behavior?
The Attribute Editor should reset, to mirror the behaviour in the scene window.