In an entry, when selecting a child category, the parent is shown as the selected item. This prevents the use of any child categories. Any help would be appreciated.
Do you have a limit of 1 set for the number of categories? Selecting a child category (Pacific Northwest) selects the parent as well, and if there is a limit of 1, then only the parent end up selected.
To work around this, you could model the regions with a structure rather than categories. Picking elements from a structure does not select the parent as well, so with a limit of 1 it would be possible to select Pacific Northwest.