List box grid lines not visible in Big Sur

[Tim_Parnell]

@Chellappan_Palaniappan

Also GUI controls are not getting updated with the .Refresh method in a loop. It gets updated only after the loop ends.

For this one, there was a discussion recently:

Refresh GUI does not work instantly in macOS 11.2.3, rather reprints the GUI only after a time consuming process

Refresh is broken. Here’s a ticket for Mojave <https://xojo.com/issue/55203> As well as one for High Sierra: <https://xojo.com/issue/51189>