src/vs/workbench/services/workingCopy/common/untitledFileWorkingCopy.ts/UntitledFileWorkingCopy/onModelContentChanged
class UntitledFileWorkingCopy:	private onModelContentChanged(e: IUntitledFileWorkingCopyModelContentChangedEvent): void {

		// Mark the untitled file working copy as non-dirty once its
		// in case provided by the change event and in case we do not
		// have an associated path set
		if (!this.hasAssociatedFilePath && e.isInitial) {
			this.setDirty(false);
		}

		// Turn dirty otherwise
		else {
			this.setDirty(true);
		}

		// Emit as general content change event
		this._onDidChangeContent.fire();
	}