Open Radar

 
Summary:
If you use multiple App Store accounts, it'll only let you update apps for the account you're signed in to. If you try updating an app from another account, you get a dialog saying "Sign in to ___ to update applications for this account". This dialog should have a button that lets you switch to that account.

Steps to Reproduce:
1. Have bought apps on multiple accounts on the OSX app store
2. Wait until lots of apps need updating, including apps from more than one account
3. Hit "Update" for an app bought on an account you're not signed in to.

Expected Results:
Either the App Store should update the app without caring which account you're signed in to (probably the best option from a UX perspective), or it should give you the same dialog as it does now, but with an extra button "Switch". Hitting the "Switch" button should present you a username and password dialog, with the username pre-filled.

Actual Results:
You get a dialog saying "You have updates available for other accounts. Sign in to <account> to update applications for that account." The only button is "OK", which cancels the operation.