Hi @Garak0410,
Which data type of the customer field within your SP list? Is it a Person type column?
I agree with @timl's thought almost. You could consider take a try to select the Customer Data card within the Edit form of Edit screen, then within right pop-up panel, click Advanced tab button, the original field name would be displayed within DataField property.
If the Customer column is a Person type column, you could consider modify your formula within the Items property of the Gallery as below:
SortByColumns(
Filter('Issue Tracker', StartsWith(Customer.DisplayName, TextSearchBox1.Text)),
"Title",
If(SortDescending1, Descending, Ascending)
)
In addition, above formula I provided may cause a Delegation warning, in order to get rid of the Delegation warning, please take a try with the following workaround:
Set the OnVisible property of the first screen of your app to following:
ClearCollect(IssueTrackerCollection,'Issue Tracker ')
Set the Items property of the Gallery control to following:
SortByColumns(
Filter(IssueTrackerCollection, StartsWith(Customer.DisplayName, TextSearchBox1.Text)),
"Title",
If(SortDescending1, Descending, Ascending)
)
Best regards,
Kris