In the current implementation of the record page, if a contextual sidebar is collapsed while the browser window is small, then the browser window is expanded, a thin strip of content is shown. The underlying cause of this issue is that the resizable-panes component calculates each pane size in percentages and is missing a max-width constrain. The end result is that a small strip of sidebar content can show up.
1. Navigate to CWF Workspace /now/cwf/agent
2. Go to Cases List
3. Pick any Case
4. Minimise the browser window till you can see Side Panel
5. Collapse the side panel now
6. Expand back the browser window to normal size
Notice the strip which is showing the content in the background.
To hide the content again, the user simply needs to toggle the sidebar after resizing the browser. This will recalculate the percentages and will hide all of the content.