How to reproduce:
1. Create a new Unity Project using the Universal Render Pipeline template
2. In the Project window Right Click and go Create -> Shader -> Universal Render Pipeline and create any of the Shader Graphs
3. Double click on the created Shader Graph in the Project window
4. In the Shader Graph window -> Graph Inspector -> Graph Settings -> Precision select the dropdown and click on any of the options
5. Without clicking anywhere else, move your cursor around the window

Expected results: The Graph Inspector doesn't move around the window
Actual results: The Graph Inspector moves with the cursor

Reproducible with: 2021.1.0a8, 2021.1.0a10
Not reproducible with: 2018.4.30f1, 2019.4.16f1, 2020.1.17f1, 2020.2.0f1, 2021.1.0a7

Note:
- Happens with all Nodes and windows of Shader Graph, which have a dropdown
- Clicking anywhere when the Node is stuck to the cursor, unties it and it stops following the cursor
- Doesn't reproduce with Visual Effects Graph
- Doesn't matter which version of the Shader Graph you use, the package is used to reproduce the bug, but it's not a package bug