Hi mtimmons,

1. If you just need to change the style of the cancel all button, please add the style setting below into your page and set style in it directly.

 <style>
.AjaxUploaderCancelAllButton {
 
}
</style>
 

2. If you want to hide the cancel all button, please try the code below

 <style>
.AjaxUploaderCancelAllButton {
 display: none !important;
}
</style>
 

Regards,

Ken