Race Condition issue when changing pages & json valid state changes

[gossi]

When composer.json is in invalid json, you modify to be valid again in the json editor and while saving change page to say overview page. Json state is valid, and thus page is enabled again but new contents are no parsed into it.
Who comes first, saving that also sets the valid state again to true and the page change which actually should parse the new contents, however doesn't already know about the valid state change and thus does nothing. Saving finishes later and enables the page which you are on already but still has the old contents.

Reproduce:

1. make sure you have something written into description
2. go to json editor, modify description which turns composer.json invalid
3. save
4. check pages they are disabled, invalid message is up in the header
5. check also overview page it still has the old value of description when it was valid
6. write something new into description, modify to make it valid again
7. hover the configuration page with the mouse
8. simultaneously hit cmd/ctrl+s to save and click on the overview page
9. overview page doesn't contain the new description value, however composer.json is valid again and saved
10. check back json editor, old description value