src/vs/editor/contrib/multicursor/multicursor.ts/MultiCursorSession/_getPreviousMatch
class MultiCursorSession:	private _getPreviousMatch(): Selection | null {
		if (!this._editor.hasModel()) {
			return null;
		}

		if (this.currentMatch) {
			const result = this.currentMatch;
			this.currentMatch = null;
			return result;
		}

		this.findController.highlightFindOptions();

		const allSelections = this._editor.getSelections();
		const lastAddedSelection = allSelections[allSelections.length - 1];
		const previousMatch = this._editor.getModel().findPreviousMatch(this.searchText, lastAddedSelection.getStartPosition(), false, this.matchCase, this.wholeWord ? this._editor.getOption(EditorOption.wordSeparators) : null, false);

		if (!previousMatch) {
			return null;
		}
		return new Selection(previousMatch.range.startLineNumber, previousMatch.range.startColumn, previousMatch.range.endLineNumber, previousMatch.range.endColumn);
	}