expanding some rows then scroll down. empty gap appears at the bottom

[mikila85]

http://ui-grid.info/docs/#/tutorial/216_expandable_grid

try expanding some rows then scroll down. empty gap appears at the bottom

[PaulL1]

@jpuri, do you have any thoughts on this one - is it an issue you've seen before?

[jpuri]

Hey @PaulL1 ,
This is a known issue with our scrolling. In case there are expandable rows it does comes.

[mikila85]

its not only at the end even just expending few, then try scrolling down LIL bit... the whole table becomes empty :(

unusable as it is.

[ddelapaz]

I am not able to replicate this issue, is it still present? I'm using v3.0.0-RC.18-d9b2314

[jacekradko]

@ddelapaz This is still an issue in 3.0.0-rc.20

[jarrodpayne]

I'm seeing the same issue here. In my case it has nothing to do with expandable rows as I'm not using that feature.

[c0bra]

The problem occurs with displaying a static number of extra rows on the bottom and top, based on excessRows, when the rows are variable height.

By default 4 rows covers rendering above/below the grid in a way that prevents gapping, normally
But when the first unrendered row is 150px tall instead of 30px, suddenly there's a big unrendered gap because you're expecting the space to be ABOVE the top of the grid.

We should be able to detect this by looking at the margin offset and the scrolltop. If the margin (i.e. sum of heights of unrendered rows) extends BEYOND the scrolltop (i.e. is larger) then we're not displaying enough rows. So in adjustRows we detect this condition and simply add extra rows until on whichever side until they display enough to extend from the top of the first rendered row to the top of the viewport.

We should not have to account for this issue on the bottom of the rendered rows.

[c0bra]

Adding a check to walk back through unrendered rows till we've rendered enough to cover the viewport is close, however we run into a problem here:

self.prevRowScrollIndex + self.grid.options.scrollThreshold

If we haven't hit the scroll threshold we won't updated the rendered row range. I'd rather not have to recalculate all the row heights on every scroll to see if we need to alter the rendered range, but it may be unavoidable...

This is only a problem scrolling upwards, as well.

[tiddle]

Just wondering what the status of this was? As this bug is happening to me without expanding rows.

[c0bra]

@tiddle It's a pretty rough issue to solve. I've spent some time tackling it but need a solid chunk that I can devote to getting a solution.

[tiddle]

@c0bra, I completely understand, is there some way of manually avoiding the issue? Or a workaround?