ScrollHeader with sticky mode is no more sticky when used with AdaptiveGridView "OneRowMode"

[touseefbsb]

I'm submitting a...

Bug report (I searched for similar issues and did not find one)

Current behavior

Sticky ScrollHeader behaves as expected when the AdaptiveGridView is in normal default mode. But when it is used with OneRowModeEnabled="true" then the header appears on the left side ( which makes perfect sense ), but on scroll towards right side ( Horizontal scrolling in onerowMode ) the header also scroll away and doesnt remain sticky with the scrollViewer.

Expected behavior

The header should be sticky even in OneRowMode enabled.

Minimal reproduction of the problem with instructions

Just set OneRowModeEnabled="true" on your adaptiveGridView and use the stiky scrollheader with it.

Environment

Package Version(s): 4.0

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [x] 2017 (version: 15.8.7)
- [ ] 2017 Preview (version: )

[skendrot]

We have discussed actually removing the OneRowMode from the AdaptiveGridView as it doesn't make sense for the control and can be accomplished by changing the items panel. This has been in a number of our breaking changes issues but yet to be complete. Because of this, I would vote to close as not being supported.

That being said, the issue isn't with OneRowMode, but with a horizontally scrolling list. It would be best to provide a sample is which the sticky header is used with a list that is horizontally scrolling

[touseefbsb]

@skendrot here u go sample to reproduce the issue : https://github.com/touseefbsb/Horizontal_ScrollHeader_Bug