With the Awesome Screenshot Firefox extension, if the background color of Firefox is set to white, this problem will appear. Please follow the steps below to solve this problem:
- In Firefox, click the three horizontal lines in the upper-right corner.
- Click Settings.
Scroll down and find "Override colors".
Set "Override colors" to "Automatic (use system settings) " or "Off".
If you still choose Custom for "Override colors", do not choose white in "Manage Colors..." > Background.