backward_to_tag_toggle

Moves backward to the next toggle (on or off) of the tag, or to the next toggle of any tag if tag is null.

If no matching tag toggles are found, returns false, otherwise true. Does not return toggles located at this, only toggles before this. Sets this to the location of the toggle, or the start of the buffer if no toggle is found.

Parameters:

this	a `GtkTextIter`
tag	a `GtkTextTag`

Returns:

whether we found a tag toggle before this