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We use Sumatra on a multi touch screen on Windows 7. Sumatra seems to recognize that there is a touch screen and it inverts the direction of the scrollbar. We have to scroll it up to go down on the document. It does that since 1.9.

Is there a parameter to disable this?

Thank you!


There is no switch for this behavior (not to mention that there are several ways to scroll and it’s unclear which one you’re talking about).

I don’t recall any code to implement such logic. It’s more likely related to driver than Sumatra.


Here is a video with Sumatra 1.9. You can see the problem. The scrollbar works correctly with Sumatra 1.8. I know it is a little bit difficult to explain with text.


Did you see the video?


Looking at the video, the behavior shown seems correct to me.

It looks like you’re doing touch/finger scrolling in which case the scroll direction is opposite to scrollbar but intuitive in that it scrolls like a piece of paper would move if you dragged it with a finger.

I don’t think the video shows scrolling with the scrollbar in that it doesn’t look like you’re actually grabbing the scrollbar and using it scroll but scrolling with touch gestures on the window’s area.

But I’m not sure if you’re saying that:

a) you try to scroll with a scrollbar and it goes in a different direction, to which I say: it’s not scrolling with scrollbar but with touch gestures

b) you’re scrolling with touch gestures but you expect it to scroll in a different direction. To which I say: we scroll the way Windows tells us so all other apps that recognize touch scrolling should scroll in the same direction (e.g. Chrome or IE or Explorer)

To put it differently: in 1.9 we’ve added support for touch gestures. One of those gestures is scrolling with a finger.

Before 1.9 we would not do anything in that case. In 1.9 we scroll the document in the direction Windows tells us.

It’s possible that for apps that don’t support touch gestures directly, the driver detects a scrollbar and sends scrollbar events in some direction, which is the opposite of what natively supported touch scroll would do but I can’t say anything definitive as I don’t have access to the exact hardware/driver you have.


We scroll with the scrollbar. You can see in the video that we use the scrollbar the second time we scroll because it is blue. Others scrollbars in Windows work as expected in this setup. It seems like the scrollbar is in the window’s area where we can do touch gestures. I think it shouldn’t be the case.

I found also this post on StackOverFlow and I tried to change the FlipFlopWheel key. It seems to work if we don’t open other windows like explorer. It is like other applications can override the effect of this registry key.

Here is two others videos I did. In the first one, you can see the scrollbar is working correctly in Explorer and in the second one, you can see the scrollbar in SumatraPDF that is working weirdly.


Sorry, I reply to you but I forgot to click the Reply link.