### Summary Concurrently editing labels in sidebar overwrites older labels without notification. ### Steps to reproduce - open issue - open same issue in new tab - change issue labels in first tab - switch to second tab: labels are not updated - change issue labels in second tab - switch to first tab: labels are not updated - reload page: labels are overwritten from second tab The same can be experienced by using the API (see https://gitlab.com/gitlab-org/gitlab-ce/issues/36945). ### Expected behavior Labels are automatically updated—at least before saving. ### Possible fixes Transfer only the labels that have changed (added or removed) and not the complete list.