I know how to do it with Clientside Row Model, simply set your column filter property to true in columnDefs. Example:
{ headerName: 'Technology', field: 'technologyType.name', filter: true },
When using Clientside Row Model, setting "filter: true" instead of something like "filter:'agTextColumnFilter'", will automatically gray out the textbox on the filter row, and when the filter button is clicked, cause a checkbox dropdown to be populated with all the possible column values.
When using Serverside Row Model, setting "filter: true", will automatically gray out the textbox on the filter row, and when the filter button is clicked, will cause a checkbox dropdown to be populated, unfortunately, with only 1 checkbox row (Select All)).
I realize that the Serverside Row Model grid, when the first page loads, could only know about all the possible values of the column for the first page of data, but it seems to me, I should be able to populate the dropdown filter checkbox rows from another datasource.
Thank you for your assistance!