What should happen:
When a user saves a skin after having added a parent skin, the skin assigned as the parent skin should belong to the user (or be public) and should match the case of what the user entered.
What happens instead:
When a user enters the name of a skin to be used as a parent skin, regardless of what capitalization they use, when the save the child skin the parent skin actually assigned will be whatever skin was first created with that name disregarding capitalization/cases. This will happen even if that skin does not belong to the user who is trying to add a parent skin.
1) make a site skin with a unique name using one account
2) switch to a different account
3) make another site skin with the same name, but different cases/capitalization
3) make a third skin and try to add the second skin as its parent
The child skin will have the first skin listed as a parent skin instead of the second skin, and if you use that child skin and inspect what css is being applied, you will see the css from the first skin being applied but not any from the second skin.