What is the purpose of the Auto Filter checkbox in the AD936X tab in iio oscilloscope ?

The tip strip mentions "Load a pre-generated filter and optimize ADC/DAC sample rates". I guess it's using one of the four possible filter in set_bb_rate(), but I'm a bit surprised this checkbox is not checked by default when no custom filter has been created.

This is exactly what happens after I start a Simulink model calling the AD936X receiver block...the "filter FIR configuration" is set to 'none' and 'Auto Filter' is left unchecked.
In addition, the and checkboxes are not visible until I select a .ftr in the filter FIR Configuration...making it a bit confusing to understand what filter is actually in use.

Since I'm sampling at a rate < 2.083MSPS, RX FIR filter must be turned on and its decimation factor must be 4. Since I get data out of the device, I know filter is turned on, but the iio oscilloscope GUI doesn't seem to reflect this. Trying to fully understand what's going on to troubleshoot an AGC Fast Attack issue that seems to be related to an incorrect RX FIR Filter settings.