the easy composer creates styles from preset loops. If you want to create a new pattern use the composer.

Either create your fill from scratch or edit a fill close to what you need by erasing tracks or notes. Triplets are then entered, either by playing then in, or in step record at the point you want them.

For step record ignore the timing position in the display for subsequent triplets, since the dots are effectively 32nd notes, so the display will not always match the timing. However if you choose triplets as the entered notes, the resulting playback will be perfect.