# ScrollViewer Slow!

**URL:** <https://forums.fusetools.com/t/scrollviewer-slow/6908>\
**Category:** Bug Reports\
**Created:** [September 16, 2015, 1:06pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908 "2015-09-16T13:06:21Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Cristian\_Karmy1](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/cristian_karmy1/32/480_2.png) [@Cristian\_Karmy1](https://forums.fusetools.com/u/Cristian_Karmy1)\
**Post date:** [September 16, 2015, 1:06pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/1 "2015-09-16T13:06:21Z")

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Hi, In my app I have a ScrollingAnimation in a ScrollViewer and in the range of the animation the Scroll slow down considerably!

this is the code:

```auto
    <ScrollingAnimation From="0" To="250">
        <Scale Target="logo" Factor="0.7" />
        <Change Target="PanelTextInputBusqueda.Height" Value="0" />
        <Change Target="HeaderPagina1.Height" Value="65" />
        <Change Target="PopularMovies.Anchor" Value="50,20" />
        <Change Target="PopularMovies.Opacity" Value="0.4" />
    </ScrollingAnimation>

```

And here a video of the problem… [https://fuseweb.azureedge.net/forum-user-uploads/2016/08/22/WUSl2OmIbfeJ-legacy-files-drGxKB1bU6Mvh2Q7-h-wpKQdSI2PvPRMbXP1tpJMC.mp4](https://s3.us-east-2.amazonaws.com/fuse-legacy-forum-assets/WUSl2OmIbfeJ-legacy-files-drGxKB1bU6Mvh2Q7-h-wpKQdSI2PvPRMbXP1tpJMC.mp4)

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<div class="post-metadata">

**Author:** ![edA-qa\_mort-ora-y](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/eda-qa_mort-ora-y/32/124_2.png) [@edA-qa\_mort-ora-y](https://forums.fusetools.com/u/edA-qa_mort-ora-y)\
**Post date:** [September 16, 2015, 2:31pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/2 "2015-09-16T14:31:06Z")

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The likely source of the problem are the three animators modifying the layout of the UI. Those are at the `Height` and `Anchor` properties. In a lot of cases we have optimizations in place to prevent needing to do a completely new layout, but there are obviously scenarios where it’ll do too much.

The way these top regions are done in some of our examples is to avoid needing a new layout on the ScrollView itself. I’m just checking now if we have a published one. It is often the layout of the ScrollView that is most costly.

One of our examples: [https://www.fusetools.com/developers/examples/scrollinganimation](https://www.fusetools.com/developers/examples/scrollinganimation)

If you can show me some more of the UX, or provide a standalone example, then I could also determine where the problem is.

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<div class="post-metadata">

**Author:** ![Cristian\_Karmy1](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/cristian_karmy1/32/480_2.png) [@Cristian\_Karmy1](https://forums.fusetools.com/u/Cristian_Karmy1)\
**Post date:** [September 16, 2015, 3:06pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/3 "2015-09-16T15:06:35Z")

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Thanks! I will modify the layout like the example. But I test the same app with a old apk (Created with a Fuse version before 0.5.0) and this don’t happen! And in general all the ScrollViewers work more smooth…

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<div class="post-metadata">

**Author:** ![edA-qa\_mort-ora-y](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/eda-qa_mort-ora-y/32/124_2.png) [@edA-qa\_mort-ora-y](https://forums.fusetools.com/u/edA-qa_mort-ora-y)\
**Post date:** [September 16, 2015, 3:12pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/4 "2015-09-16T15:12:31Z")

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Yes, it’s certainly possible that something has changed. That’s why a complete example would be great. Often it’s just something small that wasn’t captured in our test cases. Sometimes it’s a fix to another defect that has unintended results on performance.

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<div class="post-metadata">

**Author:** ![Cristian\_Karmy1](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/cristian_karmy1/32/480_2.png) [@Cristian\_Karmy1](https://forums.fusetools.com/u/Cristian_Karmy1)\
**Post date:** [September 16, 2015, 3:26pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/5 "2015-09-16T15:26:43Z")

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Its hard to me publish my app. There are many files (Uno files, js files). I will try to reprocude the same in a example…

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<div class="post-metadata">

**Author:** ![Cristian\_Karmy1](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/cristian_karmy1/32/480_2.png) [@Cristian\_Karmy1](https://forums.fusetools.com/u/Cristian_Karmy1)\
**Post date:** [September 16, 2015, 3:39pm UTC](https://forums.fusetools.com/t/scrollviewer-slow/6908/6 "2015-09-16T15:39:23Z")

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I fix the problem replacing all the animation with Move animation. But I have some Horizontal ScrollViewers with a stackPanel inside with many elements that are very slow. In previous version this Scrollviewers are very smooths. Now have many frame drops!