[JIRAALIGN-2103] UI: Slide-out "X" button overlaps with browser scroll bar

Issue Summary

Slide-out "X" button overlaps with browser scroll bar

Firefox	Chrome

• Slightly affects Chrome
• Severely affects Firefox

Steps to Reproduce

1. Browse to any grid
2. Open any slide-out that demands scrolling
3. Notice the "X" button (close slide-out) overlaps with browser scroll bar

Expected Results

• No overlap whatsoever

Actual Results

• The "X" button (close slide-out) overlaps with browser scroll bar

Workaround

• Mouse over until scroll bar disappears, then click "X" button to close slide-out