Function type for determining whether column can be dropped in a particular spot (as determined by prev_column
and next_column).
There is no replacement.
In left to right locales, prev_column is on the left of the potential drop spot, and next_column is on the
right. In right to left mode, this is reversed. This function should return true if the spot is a valid
drop spot. Please note that returning true does not actually indicate that the column drop was made, but
is meant only to indicate a possible drop spot to the user.
| tree_view |
A `GtkTreeView` |
| column |
The `GtkTreeViewColumn` being dragged |
| prev_column |
A `GtkTreeViewColumn` on one side of |
| next_column |
A `GtkTreeViewColumn` on the other side of |
| data |
user data |
|
true, if |