Although the feature you suggest would be useful in Qtractor, I'll tell you a trick.
If you click inside the box and use the mouse wheel you can change the values quickly.
Using the mouse wheel with Ctrl, the interval will jump by 10.
From what you say, using Ctrl is not an option for you (I assume you have difficult access to the keyboard, it also happens to me when I record), but it doesn't hurt to know.
Although the feature you suggest would be useful in Qtractor, I'll tell you a trick.
If you click inside the box and use the mouse wheel you can change the values quickly.
Using the mouse wheel with Ctrl, the interval will jump by 10.
From what you say, using Ctrl is not an option for you (I assume you have difficult access to the keyboard, it also happens to me when I record), but it doesn't hurt to know.