I am implementing a hidden panel that when triggered will slide in from the right side of the page and take up the whole screen vertically and roughly a third of the screen horizontally.
Would it be better to make this panel:
a) slide out over the main page, appearing to be a level above on the z-index
b) slide out and push the main page to the left, appearing to be on the same level
I personally think a) would provide for a cleaner looking UI but I can't reason why.