invisible contents builds 46-47 mac

[fbu924]

Mac OS 10.11.3. Earlybird only (stable works fine & is open now), so I'm posting here rather than in t-bird bugs, although I think it's a bug.
-No visible content in the main window. The main menu bar at top of screen is visible. This is a "standard" install mac/mac OS. Downloaded earlybird v 46 & 47 today 22march2016 (did not install at the same time, did r & r), both display the same (lack of) screen output. Am not going to OnyX (or other permissions/DU fixes) this. Thank you.

[Xeno22]

Activate HW-Acceleration:
Go to Preferences -> Advanced -> check "Use hardware acceleration when available"