Steps to reproduce :

- open the attached project
- ensure "Verify Saving Assets" is enabled in preferences
- open the scene
- select "New Material" in the project browser
- change the color to dirty the asset
- click the eye dropper in the inspector
- press Cmd+S
- attempt to click any of the buttons in the "Save Assets" dialog and notice that the buttons doesn't work

Also getting this error :

TLS Allocator ALLOC_TEMP_THREAD, underlying allocator ALLOC_TEMP_THREAD has unfreed allocations
UnityEditor.AssetModificationProcessorInternal:OnWillSaveAssets(String[], String[]&, String[]&, Int32)