CSS overflow-x: visible; and overflow-y: hidden; causing scrollbar issue

After some serious searching it seems i've found the answer to my question:

from: http://www.brunildo.org/test/Overflowxy2.html

In Gecko, Safari, Opera, ‘visible’ becomes ‘auto’ also when combined with ‘hidden’ (in other words: ‘visible’ becomes ‘auto’ when combined with anything else different from ‘visible’). Gecko 1.8, Safari 3, Opera 9.5 are pretty consistent among them.

also the W3C spec says:

The computed values of ‘overflow-x’ and ‘overflow-y’ are the same as their specified values, except that some combinations with ‘visible’ are not possible: if one is specified as ‘visible’ and the other is ‘scroll’ or ‘auto’, then ‘visible’ is set to ‘auto’. The computed value of ‘overflow’ is equal to the computed value of ‘overflow-x’ if ‘overflow-y’ is the same; otherwise it is the pair of computed values of ‘overflow-x’ and ‘overflow-y’.

Short Version:

If you are using visible for either overflow-x or overflow-y and something other than visible for the other, the visible value is interpreted as auto.

another cheap hack, which seems to do the trick:

style="padding-bottom: 250px; margin-bottom: -250px;" on the element where the vertical overflow is getting cutoff, with 250 representing as many pixels as you need for your dropdown, etc.

I originally found a CSS way to bypass this when using the Cycle jQuery plugin. Cycle uses JavaScript to set my slide to overflow: hidden, so when setting my pictures to width: 100% the pictures would look vertically cut, and so I forced them to be visible with !important and to avoid showing the slide animation out of the box I set overflow: hidden to the container div of the slide. Hope it works for you.

UPDATE - New Solution:

Original problem -> http://jsfiddle.net/xMddf/1/ (Even if I use overflow-y: visible it becomes "auto" and actually "scroll".)

#content {
    height: 100px;
    width: 200px;
    overflow-x: hidden;
    overflow-y: visible;
}

The new solution -> http://jsfiddle.net/xMddf/2/ (I found a workaround using a wrapper div to apply overflow-x and overflow-y to different DOM elements as James Khoury advised on the problem of combining visible and hidden to a single DOM element.)

#wrapper {
    height: 100px;
    overflow-y: visible;
}
#content {
    width: 200px;
    overflow-x: hidden;
}

I've run into this issue when trying to build a fixed positioned sidebar with both vertically scrollable content and nested absolute positioned children to be displayed outside sidebar boundaries.

My approach consisted of separately apply:

• an overflow: visible property to the sidebar element
• an overflow-y: auto property to sidebar inner wrapper

Please check the example below or an online codepen.

html {
  min-height: 100%;
}
body {
  min-height: 100%;
  background: linear-gradient(to bottom, white, DarkGray 80%);
  margin: 0;
  padding: 0;
}

.sidebar {
  position: fixed;
  top: 0;
  right: 0;
  height: 100%;
  width: 200px;
  overflow: visible;  /* Just apply overflow-x */
  background-color: DarkOrange;
}

.sidebarWrapper {
  padding: 10px;
  overflow-y: auto;   /* Just apply overflow-y */
  height: 100%;
  width: 100%;
}

.element {
  position: absolute;
  top: 0;
  right: 100%;
  background-color: CornflowerBlue;
  padding: 10px;
  width: 200px;
}

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<div class="sidebar">
  <div class="sidebarWrapper">
    <div class="element">
      I'm a sidebar child element but I'm able to horizontally overflow its boundaries.
    </div>
    <p>This is a 200px width container with optional vertical scroll.</p>
    <p>Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?</p>
  </div>
</div>