Use tuplets to override display quantization
You can override the display quantization value by using hidden tuplets. For example, if you want to display a single 32nd–note run in a MIDI region that otherwise contains eighth notes or longer values, you can set the Quantize value in the Region inspector to 1/8, and then drag the N-tuplet symbol onto the first note of the 32nd figure. In the Tuplet dialog, use the 8:8/32 setting, with “Hide brackets” and “Hide numbers” selected. The number (8) appears onscreen, but not when you print the score.
Although this is not the normal use of tuplets, it’s a handy way to force the display of runs of shorter note values with a display Quantize value set for longer note values.