Operating system: Windows 10 (64 bit) OS build 17134.591
Graphics card: Graphics Chipset AMD Radeon(TM) R4 Graphics
Broken: Blender 2.80 Beta Windows 64 bit March 09, 01:09:33 - a0f2923fd821
Short description of error
1# Pen settings and material properties tabs disappeared
2# An anonymous blank material comes out
Exact steps for others to reproduce the error
From 2D animation default file, switch fill tool to draw tool and the pen properties will disappear. It'll only reappear once again when I reopen the .blend file.