Background
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In our application we have a list view of contacts. In addition to the list there is a filter panel at the top of the list which provides contact type filtering through a segment control:

And also a textfield for free search of contacts underneath the segment control.
*(Above this filter panel there is also a main tab bar, so in a nutshell there are three rows of interactive controls)*

Problem
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This filter panel occupies a considerable amount of space in the view port, compromising the amount of contacts visible in the list when the user scans it. 

Therefore I'm curious about introducing the feature to fade out the filter panel when the user starts scrolling to later fade/pop it back in with a small delay after the user stops scrolling. 

![mockup](https://i.stack.imgur.com/ij6X2.png)

[download bmml source](/plugins/mockups/download?image=http%3a%2f%2fi.stack.imgur.com%2fij6X2.png) – Wireframes created with [Balsamiq Mockups](http://www.balsamiq.com/products/mockups)

Question
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My question really is whether this could be a good idea? Could it be good because it enhances list scannability, or is it possibly a bad idea because it could be perceived as obstructive or confusing when the panel keeps fading in/out upon scroll?

*Disclaimer: I'm positive that many of you will think that I should perform an A/B-test on this to find the correct approach. This will of course be conducted if this idea is moved forward, to find the correct fading delays etc. But it's not possible as of yet, I'm merely interested in hearing theoretical/factual ideas from you whether or not it could be a good idea.*