Cannot add new item to list

Where did you change the parameters of the combobox? It looks like you may have changed them in Table Design mode, rather than Form Design mode. When a form is created from a table, it copies the characteristics of the fields from the table, but they are no longer linked. So if you made the changes in the table, then they won't be reflected in the Form. 

The template almost definitely used the Lookup Field feature on the table level. Most pro developers shun this feature for several reasons. One reason is that it does not provide a NotInList event that both Ken and I talked about. If you properly code the NotInList event on the form, then there is no need to keep the Locations table open. The code will detect that the new location is not in the list and prompt you if you want to add it.

Thanks Scottgem, you are the man! Great instructions! ;)

After fiddling with my database for about 90 minutes I seem to have it mostly working. However I have to leave the newly created locations table open as a separate tab and add new locations to it as needed. What's strange is (I'm going to try to articulate this in a way that you can grasp my meaning) that once I add a new location to my location table I can choose it from the "Asset List" table, but if I click on "open" in the Asset List table to edit an existing record, if I drop down the location box from the "Asset Details" form it is still referencing the old valuelist data and not looking at the data in my new "locations" table, so I have to figure out where to change this data again. The screenshot just below is where it is NOT working properly: (notice the locations are not in alphabetical order, that's another way that I know it's pulling the data from the valuelist, not my new table)

https://learn-attachment.microsoft.com/api/attachments/b4ec4f67-22d5-43a5-bc49-5f3a51e0cb32?platform=QnA

Below you will see a screenshot of the main "Asset List" table where everything seems to be working (it looks at the data in my new table, notice the locations are also in alphabetical order) Clicking on "open" in the left column brings up the "Asset Details" form shown above.

I've clicked on "Asset Details" in the left most "Assets Navigation" area hoping this is where I go to get the non-working "Asset Details" table to work like the "Asset List" table but it's not what I'm looking for.

Anyway, I hope all of this makes sense. Right now I have a workable solution (thanks to you) but if I can at least get the "Asset Details" form to look at the new "locations" table like the "Asset List" form does I will be golden. Of course not having to switch to the "locations" table tab to add a new location would also be helpful but not an absolute necessity. I tried using the code from the link you provided (in their 3rd example) but it didn't seem to work. Thanks a million for your help! :)

What Ken said, there is absolutely no need to remove items from the Items table. All you should be doing is added a date sold field to the Items table (Maybe a price paid field as well). Then you can filter for records where the Price is or isn't null.

An alternative is to have a transactions table. These transactions will have the ItemID as a foreign key and the transaction info (date sold, price, sold to, etc.) Then you can create a Not In query (see Query Wizard) which will only list Items not in the Transactions table.

Obviously I'll need to first create a separate table for "sold items" then add another control on this table to move something from this table to the newly created table.

No.  That would be 'encoding data as a table name'.  A fundamental principle of the database relational model is the Information Principle (Codd's Rule #1). This requires that all data be stored as values at column positions in rows in tables, and in no other way.  You should have a single Assets table which includes a Sold column of Bolean (Yes/No) data type.  To return all current assets you use a query restricted to:  WHERE NOT Sold, and to return sold assets you use a query restricted to WHERE Sold.

Whew, I knew you guys would have a solution for me but it seems pretty complicated. I was a network engineer and have been a techie for most of my adult life so I should be able to figure this out with your excellent explanations, but I've already got a headache. LOL!

I've fiddled with databases in the past, even the older version of Access from the 1990's. It gets tricky and is why I chose a database that was already pre-built for me (I'm lazy!) and hoped it would work for my purposes. 

Now my next question (assuming I get this figured out) is if I sell an asset, how do I get an item that is in this table to be removed from this table and appear in a separate table of "sold items".  Obviously I'll need to first create a separate table for "sold items" then add another control on this table to move something from this table to the newly created table. I know, I need some Access training!

Hopefully that has a simpler solution. :)