1. Open and configure a project in Creator.
2. Outside of Creator, perform a shadow build of this project using a kit which is not configured in Creator.
3. In Creator, go to Projects mode, Build & Run settings.
4. Click on "Add Kit" and select "Import existing build..." from the menu.
5. Select the shadow build from step 2 and click "Open".
6. Go to "Tools" -> "Options..." -> "Build & Run" -> "Kits".
   The kit used in step 2 was added to Creator's settings.
7. Open a different project.
8. Go to "Tools" -> "Options..." -> "Build & Run" -> "Kits".
   The newly added kit was removed.

The added kit should persist just like it does when importing a build while opening a project.