I use several custom tools during the build process, mostly code generators for service references, T4 templating, and the like.
When these produce errors or warnings, they show up in the Error List window as expected. However, if I do a build, rebuild, or clean of some portion of the solution that does not touch upon the errors produced previously (say I'm not building a project that has a service reference import failure), the old list is still displayed.
Is there a way to fix that: Tool, plugin, build action, anything? I don't want to ignore the errors/warnings, only want the relevant ones to show based on what I'm doing. If not I guess this would be a request for the VS team.
Closing and re-opening the project is the only way to clear the list. From what I can tell and the research I've done, the error/warnings window is like a session log for the project. Once you close the project the log is deleted.