ObjectViewer background color issue

Whenever I clear the window of ObjectViewer by pressing Delete key, it resets background color to light gray and color cycle becomes odd (after using black and clearing objects, it sets to light gray, then as I press B, it turns dark gray, then light gray again, then normal cycle resumes).

This is build 1.5.1359.814, OS is Win 8.1.

Fixed in today's build.