How to change the target of AudioPluginHost to debug?

I’m developing audio plugins following the JUCE tutorial.
I could debug the first plugin A in Visual Studio using the file named AudioPluginHost.projucer.
But after that, when I tried to debug the second plugin B following the same process, Visual Studio debugged plugin A, not B.
I’m sorry that I cannot explain it well and I might be misunderstanding something.
But I’d like to know how to choose or change the target to debug. Thanks.

p.s. My only poor solution to this is selecting Standalone in Plugin Formats setting so that I can see the developed plugin (B, in this case). (that’s because Standalone doesn’t need AudioPluginHost, maybe)

I’m not sure I understand how your problem could be happening. But in your Plugin B’s project (not the solution), you should have the path to the AudioPluginHost, as shown in this example:

Then it just launches the AudioPluginHost automagically when you Debug Run the project. I don’t know why debugging Plugin B would somehow debug plugin A - although another possibility is the AudioPluginHost may be confused as to which plugin is which, if you haven’t bothered giving them unique different plugin codes in the Projucer > Settings.

When you open the AudioPluginHost application, it will load the previously used project file (in your case, the one you created for plugin A). So when you try to test plugin B with the APH you’re loading the project that’s using an instance of plugin A.

Create a separate APH project for each plugin and, like @stephenk showed above, load the relavent one for the plugin you want to test.