[Fix] Element.IndexPath is null after search was activated.

[alexshikov]

Fixed an issue when Element.IndexPath is null after search was activated.

DemoColoredList added to test the issue:

• CustomElement uses IndexPath to change background color.

As an option: move parent reassignment logic from DialogViewController to Section.

[migueldeicaza]

I am not sure that I understand this patch, can you tell me how to reproduce the bug, so I can evaluate the patch?

The sample is also wrong, when you subclass an Element, you must provide your own unique Key, otherwise the cells can be mixed up with other cells (likely you wont notice in this sample, but if you mix other stringelements, you would).

[alexshikov]

Steps to reproduce:

1. Create DVC with SearchBar
2. Type something in SearchBar
3. Get IndexPath for any Element

Actual result: IndexPath is null

The provided sample is the test for the bug:

• 29th line of DemoColoredList.cs is using IndexPath to set color of the cell.

Sorry for incorrect using of unique Key and trash changes in Sample.csproj.

Either I can fix pull-request or you can just close it and make fix in a better way : )