vertical scroll length should never be 0. This will result in division by 0 errors.

[Ladekarl]

If a grids viewport height, canvas height and scrollbar height has values so that the calculation:
canvas height - viewport height + scrollbar height returns 0, all the rows will dissapear when the grid is scrolled.

[dlgski]

can you provide an issue/plunker?

[Ladekarl]

Scroll the grid in this plunker all the way down, and then scroll it all the way up again.
The screen must have 1200 pixels in height (tested on 1600x1200 and 1920x1200 screens).
The chrome browser must be maximized.
Of course this issue can occur on other screen resolutions but the grid here is modified so that the issue occurs on screens with 1200 pixels in height.

http://run.plnkr.co/plunks/o8pfNE/

Before scroll:

After scroll:

[Ladekarl]

Noticed the same calculation is done when scrolling horizontally. Updated the pull request to also fix horizontal scrolling

[mportuga]

@Ladekarl I tried setting my browser window to the sizes that you mention and I don't have a scroll bar at those points. I also tried resizing my window as to get a scroll bar and I can't reproduce it.

[Ladekarl]

@mportuga could be because the viewport isn't sized exactly the same because of bookmarks or whatever. However, it should be clear from the code that a division by 0 error is plausible. Do you want me to record a video for you?

[Ladekarl]

I recorded a video: http://webmshare.com/jMJ1d