In Oracle Apex, if you have created a dynamic action to set the value for multiple items, then at runtime, it will show the processing spinner on the right side.
If it is for two or three items, then ok, but for example, if you are setting the value for more than ten fields, then it will show the spinners all over the place, which not look good sometimes.
So if you want to hide the processing spinner displayed by dynamic actions, use the following CSS trick.
Click on the page and move on to the CSS inline section and add the following CSS:
.u-Processing {
display:none !important;
}
Save the changes, and you are good to go.