How can I search for empty boxes? Sometimes I convert photos, and while editing them, I accidentally right-click while moving the mouse. This suddenly deletes a symbol somewhere in the pattern. How can I easily find (search for) empty boxes?
Those "empty boxes" represent areas of no stitches. Since they are so very common - most patterns are not full-coverage - there is no automatic way to see them.
What I do is change the background/display color to something that stands out among the stitches. An example is a bright pink when you're designing a green landscape image. Then do a "view" and if you see the pink where you don't expect it, look in that area.