I just posted a problem with the grid visibility here.
This is a quite exotic problem, but wouldn't it be nice to have a button/command to set the grid to default colors (black/white and grey/black) to enhance visibility? It should be a temporary command and it should be clearly visible on the UI that the view is altered (I understand that this interferes with the UI simplicity Igor strives for).
Similar problems may come up with any highlighted text where the contrast is quite low.
Original file view (column to the right):
Please check View > Themes > Replace document colors.