Scrollbars on *View or better VirtualFlow based UI elements

Tomas Mikula tomas.mikula at
Mon Dec 15 16:34:30 UTC 2014

Hi Werner,

On Mon, Dec 15, 2014 at 4:35 PM, Werner Lehmann
<lehmann at> wrote:
> Hi Tomas,
> On 15.12.2014 16:10, Tomas Mikula wrote:
>> To add an idea, semi-transparent scrollbars could be shown over the
>> content when the mouse approaches the edge. This would avoid
>> flickering andto save space at the same time. I realize one could not
>> use this if the scrollbars would cover some interactive controls at
>> the edge of the content.
> Sounds similar to invisible scrollbars which appear on hover only.
> Personally I don't like either one. I guess it is a matter of taste. In a
> touch scenario it is a bit of problem though because usually you cannot rely
> on hover events.

Show scrollbars on hover might be even a better idea. On a touch
device, scrollbars could be shown after an initial tiny scroll by

>> Also, I would like to see some new creative way of scrolling the
>> content, especially for cases when the full length of the content is
>> not known, e.g. a ListView with variable cell sizes, or a possibly
>> infinite stream of items that are loaded as needed. In these cases,
>> the scrollbar length always lies about the actual total length of the
>> content.
> If you have variable cell sizes an easy way to map this to a scrollbar is to
> use the number of items, possibly with some adjustments involving the height
> of the known cells. From my impression this is what virtual flow does but I
> could be wrong.

My point was that any such mapping to a scrollbar is only an estimate
of the total content length. So why bother trying to indicate the
total length by a scroll bar at all.

> An infinite stream of items can be scrolled with the "Google Picasa" light
> table approach. You can find an implementation of this concept in
> ControlsFX, see the PlusMinusSlider control.

Thanks, I wasn't aware of PlusMinusSlider.


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