Filter Gallery with Combo Box (Multi selection) which items are from Another SP List's Title Column

[sc0rpiongirl]

Hi Community,

In a Power Apps that I am working on, I need to have a multiple selection choice column which also allow user enters a new choice if currently available ones don't contain what they need.  Once they add the new choice in the Choice column, I need to have it available for everyone's future use.  I know it'd be easily added directly in SP List end, but the ask is to allow user to add the choice.

I did some thorough search and from what I read, there is no direct way to realize what I mentioned earlier.  I could allow user to enter a new choice but that value won't be captured as one of the new selection in the Choice column.  I read another post (https://powerusers.microsoft.com/t5/Building-Power-Apps/Adding-More-Options-To-Choice-Column-In-The-...) that suggested using another List with single column which populate the choices, then use that column's value as Items in the master list combo box.  This seems to work well.  I managed to have the multi selected value populated in the master list as Text type using Concat ", " to separate them.  The problem I have now is I can't figure out how to filter the gallery using the Master list as data source to find the entries in which tag with those multiple selections.

Here is the scenario and the codes I have: The combo box is retrieving all "Risk Tags" from another list (one column), in the master list, there is a column named "Risk Tags" with data type single line of Text.

- In the Edit form, I inserted a data card "Risk Tags" from the master list, and replaced the default DataCardValue text input box with a Combo box - ComboBox1,

Items = 'AnotherList'.Title

- For the Risk Tags Data Card, I added code Update property which will be visible when the form is in View mode:

Update = Concat(ComboBox1.SelectedItems, Title, ", ")

  When tested, selecting multiple items in the combo box then hit save the form, the "Risk Tags" column in the master list shows the result as expected, eg "Risk 1, Risk 2, Risk 5"

In another screen I have a gallery with data source as the master list, I need to use a combo box to filter the "Risk Tags".  However, I couldn't get it working.  Here is my code: (didn't throw any error but when selecting any risk from the combo box, it will show nothing. The name of the combo box on this screen is comTag with items = 'Another List'.Title

Filter(
'Master List',
IsBlank(comTag.SelectedItems.Title) || IsEmpty(comTag.SelectedItems) || true in ForAll('Master list'.RiskTags, ThisRecord.RiskTags in comTag.SelectedItems.Title)
)

Any help would be greatly appreciated.  Many thanks!