Sets the character to use in place of the actual text in “password mode”.
See [[email protected]_visibility] for how to enable “password mode”.
By default, GTK picks the best invisible char available in the current font. If you set the invisible char to 0, then the user will get no feedback at all; there will be no text on the screen as they type.
| this |
a `GtkEntry` |
| ch |
a Unicode character |