Active solution platform vs. platform vs. platform target

I need to build one of the projects of my solution in x86. I open Configuration Manager and see the following:

But I don't get how are "Active solution platform", "Platform" and "Platform target" (on project properties Build tag) related.

Visual studio provides a solution wide platform option, which allows you to switch the platform for all projects. Or, you can use a project specific platform option.

Platform target is to switch between targeting a specific SKU. Platform target exposes the different versioning options, e.g..NET Framework v2.0, 3.0, 3.5 and 4.0, as well as the Client Profile variants.