An option on the General tab page of .NET Windows Forms and Web Forms Project painters allows you to choose whether to do a full rebuild or an incremental build when deploying a .NET project. The default option is incremental.
If the application has not been previously deployed, a full build is triggered by the PowerBuilder IDE even when the incremental rebuild option is selected. The incremental rebuild option is also overridden if you remove the build directory that PowerBuilder generates from a previous build, or if some of the build files are missing or damaged in the build directory or its subdirectories.