I'm actively using the code folding feature; scrolling is also a bit uneven without it but when there are folded lines it gets really like rolling on a bumpy road. No matter how I scroll - using the mouse wheel does the same thing as moving the scrollbar. With arrow keys the cursor motion slows down as if it was difficult for the program to calculate the "next visible line" and I suppose it really is; however on a 2.4GHz computer with a relatively small (70-80k) file it should not be like this.

Does anyone else have the same problem?
Is there a chance to improve this in some future version or "it's like that, period"?

I opened a *.c file with 216 KB, used View - Hide/Show Lines - Collapse All. Only 16 displays remained visible after this action from more than 4000 lines of code.

Scrolling with the keys Up, Down, Page Up and Page Down as well as with the mouse wheel was okay. No delays, smooth scrolling, even with Ctrl+Up and Ctrl+Down (scrolling display instead of caret). But interesting was to see what happens with the vertical scroll bar. It's size and positioned changes according to how many lines are currently visible in comparison to total number of lines and current position in file. I have observed this behavior never before because always looking only on the lines when scrolling which I do always by keys. I must add that I set the key repeat rate in the Windows keyboard settings to maximum. Also pressing mouse wheel shortly (mouse pointer changes to a point with 4 arrows) and scrolling now with moving the mouse up/down works quite well.

Left clicking on a free area on the vertical scroll bar to jump the display within the file works also as expected.

But when scrolling with clicking with left mouse button on the vertical scroll bar and drag it, I can see rough scrolling of the display. The reason might be that the bar wants to update its size and position, but cannot do it as this is blocked as long as the bar is hold with left mouse button. So I suggest not to scroll with this method if lines are hidden.

dkellner wrote:Is there a chance to improve this in some future version or "it's like that, period"?

This question can be answered only by the IDM developers after analyzing the issue deeply, but not by a user.

Thanks Mofi, and yes, maybe my case is special because my keyboard speed is tuned way beyond the "maximum" 30 kps. It's done with some accessibility tool, I can't remember which one, I've set it once and forgot about it - anyway now I have a key speed about 80 kps. Maybe with this speed, UE scrolling simply can not keep up.

BUT.

When you do mouse wheel scrolling with the folded lines closed (just check it a second time pls), one tick with the wheel will only scroll ONE line down as long as you have a folded block on the top of the screen. At least this is the case for me. If I have a lot of collapsed blocks (each bigger than the number of lines a single wheel tick should jump), I realize that scrolling will not go faster than one block at a time - which is, since they're collapsed, one row at a time.

If this works differently in your case, please let me know.

dkellner wrote:... anyway now I have a key speed about 80 kps. Maybe with this speed, UE scrolling simply can not keep up.

Yes, 80 key events per second is definitely too much for any application as screens have nowadays a display refresh rate of 60 Hz. So there are only 60 display refreshes per second possible. And with such a high rate Windows has to switch very often from keyboard driver to event and task management to task with focus and back to keyboard driver. With a high rate of hardware interrupts processed with a higher priority than application processes every system can be killed. There is a reason why the maximum 30 kps was not changed in the last 30 years. The reason is that whether the computer hardware nor the OS nor human beings can really process such high update rates. Our human brain cannot even process 20 pictures per second.

dkellner wrote:When you do mouse wheel scrolling with the folded lines closed (just check it a second time pls), one tick with the wheel will only scroll ONE line down as long as you have a folded block on the top of the screen.

You are right, good watched. Indeed the display scrolls on a single mouse wheel spin only 1 displayed line instead of the number of displayed lines as defined in the mouse settings if the line at top of the document window is the first line of a folded block marked with [+] symbol in the code folding gutter.

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