Scrolling bug?

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Vanceone
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Joined: 2013-05-03 07:06:31

Scrolling bug?

Post by Vanceone »

I'm running Nisus 3.3 (most recent) on Monterrey, on an intel Mac.

I'm getting intermittent scrolling bugs. What happens is that I cannot scroll (using scroll bars) away from the page that has the cursor on it. The page "bounces" as it tries to move, and then immediately resets. The "pill" I think it's called in the scrollbar can move, but when the mouse is released it immediately snaps back to the location with the cursor.

I haven't detected any sort of pattern, although most of the time it seems my cursor is in either a footnote, a footer, or in a table cell. Scrolling by moving the cursor is unaffected (like with the arrow keys or something).

If I click on a different place on the screen, thus moving the cursor out of its position, scrolling again works. Like I said, it's intermittent and not reproducible.

Any ideas? Have I found a nasty little bug?

My guess is somehow the NS Scrollview is resetting the scroll position to the cursor position repeatedly, which would explain the "bounce" I'm seeing.
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martin
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Re: Scrolling bug?

Post by martin »

That sounds like an irritating behavior. I'm glad that you have a relatively simply workaround to break out of autoscrolling jail. Offhand this sounds like a bug in Nisus Writer, though macOS could also be a factor.

One question: when you say the "page" bounces do you mean that the top of the page is neatly scrolled to the top of the viewing area? If so, that sounds like the scroll area is stuck in per-page scrolling mode, i.e. the scrolling you would see if you set the zoom to keep the entire page in view and pressed the Page Up/Down key.

Or is the unwanted autoscrolling less consistent about what is scrolled into view? e.g. maybe you are scrolled halfway down the page. If this is more like what you are seeing, then I'd ask if there's any other noticeable pattern to the scrolling? e.g. your selection is always vertically centered.

One last question: are you using typewriter scrolling or synchronized scrolling?
Vanceone
Posts: 197
Joined: 2013-05-03 07:06:31

Re: Scrolling bug?

Post by Vanceone »

Not using typewriter or synchronized scrolling.

I think you are asking if the part that bounces is to the top of the page, not the viewport top. That answer is no. I frequently run a zoom level of 150% or 200%, so the entire page is almost never entirely visible.

Thus, the "viewport" or the visible area of the page that contains the cursor is the one that "bounces." Invariably, if I scroll up (or down) when this bug happens, I can scroll the view port as much as I want until the insertion carat would scroll off the visible part of the viewport. (I'm suing viewport to mean the section of page that is currently on screen; I think that''s the usual definition).

Once the insertion carat would scroll off or out of view, the viewport "bounces, keeping the line or cell or whatever where the insertion carat is currently located, on the screen. So it 'bounces" approximately one line, repeatedly, as the scrollbars attempt to move the viewport, and then the autoscroll or what not kicks back in to reset the view port.

The behavior is almost like this: When you have the carat (I'm using carat here because sometimes the "cursor" is labeled as the mouse pointer, and sometimes the insertion carat--I am referring to the insertion carat) offscreen in some text, you can arrow right or left or whatever, and Nisus will auto-scroll your viewpoint to that carat location. When this bug occurs, the behavior is almost like Nisus is triggering that auto-scroll every time the insertion carat goes out of the viewpoint. So the viewpoint automatically scrolls back to keep the carat on the screen. But you are still moving the scrollbar "pill" so once again the viewpoint moves, and then the autoscroll kicks in again. Essentially, the view port becomes "locked" to always keeping the insertion carat in view.

This happens whether you are dragging the scrollbar pill, or just clicking in the scroll bar area to move the viewpoint one screen at a time. I have to move the insertion carat somehow to a different spot in the text to release the "lock" and allow scrolling to work again.

Wish I knew how to trigger this bug reliably. I haven't diagnosed it down yet. I hope this information is helpful!
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martin
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Re: Scrolling bug?

Post by martin »

Thanks for the additional explanation!

I think to investigate this further we'll need you to use a special debug version of Nisus Writer. We can try to capture and log the source of the unwanted auto-scrolling. If you're willing to help continue the investigation, please send me an email directly at:
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