ProjectTemplate solution is pulling in CanvasLayout

[Arlodotexe]

Repro steps:

1. Generate and open the "All" solution.
2. Build at least once
3. Close the "All" solution and open the ProjectTemplate solution
4. Build and deploy the app. UWP was used to test this, but any platform should work.
5. CanvasLayout sample markdown is being pulled. Select the "Canvas Layout" tab, and observe the KeyNotFoundException caused by the sample metadata for CanvasLayout not being present in the solution.

[mrlacey]

A repro is even easier. Running the generate all script and building in advance aren't necessary.

Files in all labs are being wildcard included (I think by Labs.Head.props - although it could be another path used by the SourceGenerators) in every version of the sample app.

Doubly verifiable by the code in #102 as this adds a second experiment.
Opening SizerBase.sln in that branch and running the sample app also includes CanvasLayout tabs.
Opening CanvasLayout.sln in that branch and running the sample app also includes tabs relating to SizerBase.

[michael-hawker]

Thanks @mrlacey, I can take a quick look, this may be tricky as we're trying to wildcard and make it simple. Wonder if we'd have to filter by path in the code that's loading/looking at the documents for the tabbed page, but that's going to slow things down compared to the generated code just not containing stuff.

Could have the generator look for a compilation flag we have for this mode, and use that to do the filtering maybe... 🤔

[mrlacey]

I get that the all sln needs to wildcard. It seems as though the individual experiments shouldn't be using that same shared props file.

[Arlodotexe]

I get that the all sln needs to wildcard. It seems as though the individual experiments shouldn't be using that same shared props file.

Using the same props files isn't an issue. The properties in these files are pulled into the csproj directly, and any paths in the props files are relative to the csproj, not the props file. That's why we use "absolute" paths
relative to the repo root in so many places.

It's likely caused by the wildcard path which starts at the solution root, that might have a bug in it.