Using Perspective 8.1.26 and Chrome browser on a touch screen, to resolve the problem that the text on a button was selected with a long press on the button, under Styles, I added the stylesheet.css with the entry:
* {
-webkit-touch-callout: none; /* for Safari on iOS only */
-webkit-user-select: none; /* for Safari */
user-select: none;
}
(The entry was suggested in Perspective Mouse event, disable cut/copy/paste on iPad - #11 by Chris_Kociolek; the * means the styling will apply to every component)
For individual components, adding the key value pair of "user-select: none" in the textStyle properties of the component also works.
Adding the event handler suggested in Perspective disable right click menu on touchscreen did not work.