Clicking a color menu causes the default scrollbar to appear too

[Kenny2github]

Expected Behavior

Clicking the color menu should work normally

Actual Behavior

When clicking a color menu (like the one in set pen color to []) the default scrollbar appears (like in #548)

Steps to Reproduce

1. Navigate to the pen blocks menu
2. Click on the color menu in set pen color to []
3. Move the mouse to the Stage and scroll down
4. White space below editor shows (why is there that space?)

Operating System and Browser

Windows 10 Chrome 58

[paulkaplan]

Woah interesting bug! I'm going to file this on scratch-blocks, since it actually originates and will be fixed there, but I'll leave this open as a reference until that one is closed. Thanks!

[chrisgarrity]

tracking in scratchfoundation/scratch-blocks#1023

[Kenny2github]

@chrisgarrity @paulkaplan deliberately left this open...