**Yes, it is a bug!**
A hotfix was made available on the 4-Oct-2018 from Micro Focus, for this very issue; Cannot set parameter to ''same line as'' in parameters list settings when few parameters exist. It keeps defaulting to ''sequential'' 
The Solution for both LR 12.60 and PC 12.60 environments: 
 1.  Download theHotfix ''Fix99994.zipand unzip the downloaded file. It contains a fix for each language including English (default installations are in English)
 2. Close VuGen and Controller, if open
 3. Take a backup of the original''paramui.dll'' in the [LoadRunner Installation Folder]bin folder
 4.  Place the selected language paramui.dll file from the zip file into [LoadRunner Installation Folder]bin
 5. Reboot
Do this on ALL PC host (Controller) machines and ALL standalone VuGen machines.
IF you are a **Orasi Support Customer** please open a case to get this hotfix. A case can be opened:
* At http://SupportWeb.orasi.com
OR
* By email to hpsupport@orasi.com 
OR
* by Phone 678-819-5315
Additionally, on the Micro Focus support site you can get the hotfix by searching for KM03263663