Creating a measure displaying whether a value in row is selected or not

If this is the reason then the only other method i can think of is to colour each line based on the text value.

as power bi does not allow conditional formating based on text only number then you would need to create a rank for each of the values. for example 

Measure = RANKX('table'[TEXTTOCHECK])

You can then use this Rank Measure in a conditional fomat using a rule and give each rank a diffrent colour.

this would not allow you to see based on a selected value but might still give the view you are looking for by looking at the colours between each of your choosen colour

This would look something like this 

There May be a way to conditionaly format the rows based on rank and a selected value in a slicer but im not sure i will explor this