Select dmx-on:changed doesn't run function but dmx-on:blur does

Can anyone explain why this works using dmx-on:blur

<select id="select2" class="form-control" dmx-bind:options="sc_tripbits_list.data.query1" optiontext="title" optionvalue="tripbit_id" dmx-bind:value="context.custom.tripbit_id" dmx-on:blur="updateImage('{{public_id}}','{{select2.value}}')"></select>

but dmx-on:changed doesn’t?

<select id="select2" class="form-control" dmx-bind:options="sc_tripbits_list.data.query1" optiontext="title" optionvalue="tripbit_id" dmx-bind:value="context.custom.tripbit_id" dmx-on:changed="updateImage('{{public_id}}','{{select2.value}}')"></select>

dmx-on:updated doesn’t work either.

Thanks,
Heather