src/vs/workbench/contrib/mergeEditor/browser/view/viewModel.ts/MergeEditorViewModel/setActiveModifiedBaseRange
class MergeEditorViewModel:	public setActiveModifiedBaseRange(range: ModifiedBaseRange | undefined, tx: ITransaction): void {
		this.manuallySetActiveModifiedBaseRange.set({ range, counter: this.counter++ }, tx);
	}