Newly rendered scrollable positioned incorrectly when browser scrollbar triggered

[julianlam]

Assuming a website is designed in such a way that the content is resized to fit the user's screen using javascript. An increase of even 1 pixel will cause the browser's scrollbar to appear.

As Scrollable now works similar to tips, in that the element itself is rendered at the bottom of the page, this inadvertently causes the scrollbar to appear for 50 milliseconds, before .reposition(); causes it to go away.

However, the mere presence of the scrollbar causes .reposition(); to calculate the final left value incorrectly, and thus it is moved to the wrong location.

Defining top and left starting values in the scrollbar container's CSS fixed this problem.

Fix has been pushed to master.

[julianlam]

There was a related display bug in which the knob was visible for 50 milliseconds, as the default style for the container/knob is visible.

Setting a default opacity of 0 (and hidden visibility) and rigging initialize(); to force the element to show fixed the problem.