Charscreen editor to highlight where char is used

[mokdevel]

In charscreen editor->Screen, I pick the character to use from the right side which shows the charset. Would it be possible to highlight on the Screen (left side), where on the Screen the selected character (from the right) is used?

Example from c64: I pick A ($01) from the right side and it's highlighted in transparent blue. I'd like to see all screen chars highlighted with transparent blue on the Screen.