Sharing dashboard with multiple groups caused users to lost ability to edit the dashboard

Issue Summary

Users are unable to edit a dashboard if the dashboard is shared with multiple groups.

Steps to Reproduce

Have the following configuration:

• group1 - member is user1
• group2 - member is user2

How to reproduce:

1. Create new dashboard
2. Grant editor permissions to group1
3. User1 is able to edit dashboard (expected)
4. Grant editor permissions to group2 OR to user2 individually
5. User2 is unable to edit dashboard (not expected). User2 is able to view the dashboard but the "Edit dashboard", "Add Gadget" and "Edit layout" options are missing.

It seems that only the group permissions takes precedence while any subsequent group/users are ignored.

Expected Results

User 2 should be able to edit the dashboard, as the user is a member of "group2" which has edit permissions.

Actual Results

Members of the "group2" group cannot edit the dashboard

Workaround

1. Grant edit permissions to a single group and make sure all the relevant users that need to edit the dashboard are part of this group
2. Grant permissions to individual users manually.