Windows 10, GTX1080Ti
Broken: 2.8 and prior
Worked: Probably never
Short description of error
Whenever I try to edit any hotkey assignment in Screen\Screen Editing section of the keymap editor, exported keymap becomes completely corrupted when re-imported. This happens due to the fact there some hard-coded values for input action field. When keymap is exported, these fall back to the incorrect "Press" action, and when the keymap is reimported, press of any button with related modifier key assigned to the screen editing operations, such as Ctrl or Shift will trigger a window operation, making the entire keymap unusable.
The only solution for this is to manually open exported .py keymap file, and remove the entire screen editing section. This also means it is not possible to customize any keyboard shortcut present in the Screen Editing keymap section.
Exact steps for others to reproduce the error
1, In User Preferences window, Input panel, navigate to Screen/Screen editing section.
2, Change "Toggle Header" key mapping to a different key. This will trigger saving of the Screen Editing section into a keymap file.
3, Export key configuration
4, Restart Blender
5, Import the exported key configuration
6, Try to perform basic blender tasks that require Shift or Ctrl modifier key.
7, Notice screen editing actions happening instead.
Solution for this problem is to make Blender's keymap editor recognize these special input action values and save them correctly within the keymap file.