There has been a similar discussion also for Buttons here: [FR] Buttons: add option to ignore clicks with right mouse button
The problem with ignoring right-clicks at the Component level is that, if implemented in the same fashion as setInterceptMouseClicks() does, it prevents the usage of right-clicks entirely, but they come handy sometimes, e.g. to open a pop-up menu.
The ideal would be to have a method in Slider, and one in Button, to say: don’t perform your main action when the right (secondary) mouse button is pressed, but only when it’s triggered with the left (main) button.
One such “property” could be even set in the Component base class, but what is done with it should be implemented specifically for every widget where that makes sense, while still allowing right-clicks to trigger listeners and callbacks for those widgets