Fix sets manager import form selection multiple default option selected issue.

[drgrice1]

Currently when the sets manager page loads the "Import how many sets?" select has "a single set" initially selected and the "Import from where?" select has "Select filenames below" selected. But then if you change the first select to "multiple sets" the "Import from where?" select still has "Select filenames below" selected. Furthermore, if you then click on that select and use shift-down arrow to select multiple sets, that first disabled option stays selected. Then form validation fails for that option since it has no value if you click the "Import" button.

This just makes it so that when you switch from the "Import how many sets?" select from "a single set" to "multiple sets", that first option in the "Import from where?" select is immediately unselected.

There is also a little clean up of this section of JavaScript code. The elements with id import_source_select and name action.import.number are actually the same element, so no need to find them in the DOM twice. Also ensure the elements exist and are found before trying to work with them. More of this is needed in this file, but this is probably good enough for now.

[pstaabp]

fixes the issue.

[somiaj]

This fixes the issue you mention, and currently now if you select multiple sets, no filenames are selected, but if you then select single set again, the first set definition file then selected. Would it be reasonable to return this back to the place holder "Select filenames below". Also "Select filenames below" is plural even in the case only a single file name is selectable. Unsure if that is worth cleaning up (though with translations might need to store both translations as data attributes).

[drgrice1]

We could make the plurality of "filenames" be responsive to the select type, but I don't think that it is a good idea to make it so that the place holder is selected when switching from selecting single to selecting multiple sets. Perhaps you didn't notice that if you have it set to select a single set and select a particular set, and then change to selecting multiple sets, that single set stays selected. So it happens consistently both ways.

Furthermore, there are advantages to that behavior. For example, I have a long list of set definitions, I have selection single selected, and I scroll down and select one set. But then see another set near it that I want to also select, so I want to change to selection multiple. When I do the set I previously select is still selected, and now I can add to that selection.

I see zero benefits from changing that behavior.

[somiaj]

I agree that if something is selected it should stay selected, I was talking about the case that nothing is selected, then switching back to choosing single set causes the first item to become selected.

Looks like in my edits of the message before I posted, I deleted a sentence that mentioned if items are selected then the first item should still stay selected.

[drgrice1]

There doesn't seem to be much that can be done about that case. When the change event occurs the first option after the "select filenames below" option is already selected. Probably this is some default browser behavior that causes it to be selected. And so you can't know if it is selected because the user did so, or because of this default browser behavior.

That is not to big of a deal, and I don't think it will cause major confusion though.

[somiaj]

Agreed, and really will probably only occur when testing things. Very unlikely someone is going to switch from single set to multiple sets, then back to single set without selecting something. Just an observation I made on behavior in my browser.

[somiaj]

Works well. Fixing the plural issue is very minor, so I approve either way.

[drgrice1]

I found out that I was checking the value of the action.import.source select to late in the method. If you check it before the size and multiple attributes are changed, then it does have the selected option when switching from multiple to single. So now if you switch from multiple to single with nothing selected, the first default option is selected.

As to the plurality of the wording, note that this code also has an untranslated string the javascript uses. Namely (taken from filenames) for the action.import.name input. This code is very old, and is from before I started adding this data attribute translation approach. That could be updated.

[drgrice1]

I went ahead and fixed the plurality and translated that other string.