These instructions apply to OnePager v5.3 or earlier. If you are running OnePager v6.0 or later, please read this article instead.
OnePager is capable of using any Microsoft Project/Excel field for any purpose (e.g. swimlanes, conditional formatting, task labeling, etc.) However, only a select number of fields are imported by default from Microsoft Project/Excel into OnePager when you create your new project view. This is done for performance reasons, as importing several hundred Project/Excel fields all at once would seriously degrade OnePager's performance.
If you are attempting to use a Project/Excel field for a particular purpose, but do not see it available in the Project-View Properties form, this means that the custom field was not specified in your initial template when you first created the project view.
To remedy this, click the Templates button next to the OnePager button in Microsoft Project/Excel:
Navigate to the feature (e.g. swimlanes, colors) where you want to use the custom field. You will notice that when you click the dropdown in the template, the full list of MS Project/Excel fields is available, instead of the limited list that is available in Project-View Properties:
Ensure that you have selected all of the correct fields before creating your view. If you're not sure which fields you want to use, you can always go to the Other Columns tab of the Templates form, and map some more fields into the Extra fields slots for future use -- even if you're not sure how you want to use them yet:
From there, Save the template, and then Create a New Project View. Unfortunately, changes to templates cannot be retroactively applied to existing project views. This means that you cannot shoe-horn a custom field into a project view that already exists, if the field wasn't there to begin with. However, once you have made the necessary changes to your template, any NEW project views created from that template going forward will have your custom MS Project/Excel fields available instead of the standard set.
Please let us know if you have additional questions at firstname.lastname@example.org.