Thanks for contacting Syncfusion Support.
In GridDataControl you can clear filter collection by using the GridDataVisibleColumn.Filters.Clear method like the below code example,
We have prepared a sample for switch the FilterBar and the regular funnel filters using the CheckBox and you can download the same from the below location. In this sample filtering is working fine from our side. If this solution does not meet your requirement could you please share the exact requirement of GridDataControl filtering in your application. It will be helpful for us to analyze further.
Please refer the below UG link for know more about the Filtering
UG Link : http://help.syncfusion.com/wpf/griddata/data-presentation#filters-collection
We have checked your reported issue with our sample. But we were unable to reproduce the issue. Filtering operations is working fine when we switch the FilterBar and regular filters. For your reference, we have attached the tested video in the below location. Could you please revert by modifying the previous updated sample based on your application and share the details about which Syncfusion Version you have used in your application. It will be helpful for us to analyze further.
Video : http://www.syncfusion.com/downloads/support/forum/121931/ze/Filter-1568422022