Channel manager: Edit mode: Edit content on the page - Nothing happens when user clicks on "Edit content on the page" in template composer edit mode

1. Log-in to CMS
2. Navigate to channel manager
3. Select any channel >> click on open channel >> Click Edit on tool bar
4. Now you should see template composer plus the tool bar with "save & close" and settings options
5. Now click on "Edit content on this page"
6. Editable content should be highlighted against darkened background
7. Click on "editable area"

Actual - Nothing happens
Expected - Respective document should be displayed in edit mode

Note - This is a duplicate functionality, "Edit content on this page" is already available in "preview" mode.
I feel this should be disabled in Edit mode