Lightweight vs Full Solution Load for Mixed‑Language Solutions: Does Project Count or Language Type Drive Automatic Threshold?

Visual Studio automatically switches to Lightweight Solution Load when a solution exceeds a project‑count threshold, defaulting to 25 projects in VS 2022. For solutions that mix C++ and C# projects, it is unclear whether the threshold evaluates only the total number of projects or also the language type, leading to inconsistent activation and on‑demand loading latency during concurrent access such as Live Share.

The key decision involves identifying the exact criteria that trigger Lightweight Load and how language composition influences that behavior, while respecting the undocumented heuristic and its impact on extensions that assume full loading. Does the automatic threshold consider project language type or solely project count? How does the threshold adapt when a solution contains both C++ and C# projects? Is there a documented way to influence this decision beyond manually toggling Lightweight Load per solution?