src/vs/workbench/common/editor/sideBySideEditorInput.ts/SideBySideEditorInput/capabilities
class SideBySideEditorInput:	override get capabilities(): EditorInputCapabilities {

		// Use primary capabilities as main capabilities
		let capabilities = this._primary.capabilities;

		// Trust: should be considered for both sides
		if (this._secondary.hasCapability(EditorInputCapabilities.RequiresTrust)) {
			capabilities |= EditorInputCapabilities.RequiresTrust;
		}

		// Singleton: should be considered for both sides
		if (this._secondary.hasCapability(EditorInputCapabilities.Singleton)) {
			capabilities |= EditorInputCapabilities.Singleton;
		}

		return capabilities;
	}