In Pega 7 we can enable filtering on a report. The filter will display values with checkbox for each and a search text box. Is it possible to provide multiple values i search text box to search for all of them.
Entering multiple values separated by a comma in the search textbox of the filter will not give the result you expect. Actually, with the current Pega design, you're supposed to enter only one value in the text box.
Even with customization we cannot achieve your requirement of using multiple values to filter Reports or Grids sourced with ReportDefinitions.
If using pagelist sourced Grids, then you can probably do custom filtering to achieve the above requirement.