Thin strip of content is shown in the background near side panel when the browser window size is expandedDescriptionIn 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.Steps to Reproduce 1. Navigate to CWF Workspace /now/cwf/agent2. Go to Cases List3. Pick any Case4. Minimise the browser window till you can see Side Panel5. Collapse the side panel now6. Expand back the browser window to normal sizeNotice the strip which is showing the content in the background.WorkaroundTo 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.Related Problem: PRB1452976