It’s been a while since we introduced mice that do “smooth” scrolling instead of “detent” (bumpy) scrolling. However, we’ve noticed that some applications still don’t support scrolling anything less than a full line at a time. When a detent wheel scrolls across a bump, it sends a message to the application to scroll one line, which in computer terms means it sends the number 120. If you have a wheel with no bumps, each little wheel movement sends only a part of a line (30 instead of 120, or ¼ of a line). The result is a nice smooth effect in applications like Word and Internet Explorer that support partial scrolling.
Unfortunately, some applications aren’t programmed to process anything that isn’t a multiple of 120. Either they are “eager scrollers” and lurch forward when you move the wheel even a tiny bit, or they are “shy scrollers” and don’t do anything unless they see a multiple of 120, leaving you to think the scroll wheel is broken. But the problem is not the wheel, it’s how the application handles the messages from the mouse.
To help improve the experience, we’ve updated an article in the Microsoft Developer Network library to give programmers the best information about how to handle partial scrolling. We also changed our Mouse software (IntelliPoint) so that the latest version (8.0) has a list of applications that we know don’t support partial scrolling. When IntelliPoint 8.0 detects one of these “shy scrollers” or “eager scrollers”, it will step in and add up the partial scrolls for the application, and then send the scroll message when it reaches a full line.
We’re also exploring other ways to help you work around this challenge. One idea is to develop a user interface where you could manually add applications to the list of applications that don’t support partial scrolling. Another idea is to include the ability to turn off partial scrolling completely — you’d lose the nice, smooth scrolling effect in applications where it works, but the programs that don’t support partial scrolling would scroll.
Here’s the feedback we’d like from you:
- Share your thoughts on our ideas for working around the partial scrolling issue, or share your own suggestions.
- Tell us the names of applications where you consistently see problems when scrolling, so we can investigate them and possibly add them to the list.
Thanks for your assistance. We really value your feedback!