Hi, I'm running Windows and somewhere between 2.1.2 and 2.1.5 things have gone wrong for the Inc/Dec sliders.
To reproduce it: add a slider, select "Inc/Dec buttons" for type, set interval to 1, press ctrl-T to test the component and click on the + and - buttons. The values won't get decremented and incremented as you would expect.
Anyone else can confirm?