How to reproduce:
1. Create a new project
2. Import the Profile Analyzer package from the Package Manager
3. Open the Profile Analyzer window (Window -> Analysis -> Profile Analyzer)
4. In the Profile Analyzer window click the Compare tab and load the attached data (capture1.pdata and capture2.pdata)
5. In the Single tab set Marker Columns to 'Time and Count'
6. Right-click over the Marker list header and select '1st' to be displayed (notice the Marker Column now changes to 'Custom')
7. In the the 'Compare Tab' set Marker Columns to 'Time and Count'
8. Right-click over the Marker list header and select 'Count Right Frame' (notice the Marker Column now changes to 'Custom')
9. Switch back to the Single tab (notice that 'Custom' Column is displayed)

Expected result: 'Custom' Marker Column displays the '1st' column
Actual result: 'Custom' Marker Column does not display the '1st' column and looks identical to 'Time and Count'

Reproducible with: 0.5.0 - preview.1 (2018.4.20f, 2019.3.7f1), 0.6.0 - preview.1 (2020.1.0b4, 2020.2.0a5)
Could not test with package versions: 0.4.0 - preview.3 (unable to load data), 0.4.0 - preview.5, 0.4.0 - preview.6 (Marker Columns not introduced)

Notes:
Setting the Marker Column to anything else and then setting it back to 'Custom' fixes the issue ('1st' column gets displayed)