Straight lines disappear in the Share -> Whiteboard space

[DeucesStu]

Hi there, 

I use Zoom for teaching, and prefer the functionality of the Whiteboard that is embedded within the "Share Screen" function (rather than using the whiteboard button). I access this through Share Screen -> Whiteboard whenver I have a meeting. 

The teaching I do involves graphs. I often have to draw axes, for example. Recently - but not previously, so perhaps as a result of an update - I have encountered a problem when looking to extend or move straight lines. I hold down the SHIFT key to ensure the lines I draw are exactly horizontal or vertical and, once drawn, I sometimes need to extend these or move them around the whiteboard. When I do this, the line completely disappears, meaning I cannot see where I am moving it to, or whether I have indeed selected the line at all. This doesn't appear to happen when I do not hold down the SHIFT key. Sometimes the line have draw is duplicated, rather than disappears. 

Does anyone have a solution to this? I have updated Zoom, and reinstalled. My software is up-to-date.

Stu