diff --git a/notebooks/visualization/src/com/intellij/notebooks/visualization/outputs/impl/NotebookOutputCollapseAllInSelectedCellsAction.kt b/notebooks/visualization/src/com/intellij/notebooks/visualization/outputs/impl/NotebookOutputCollapseAllInSelectedCellsAction.kt
index d11aaebc1bac..bcf9ccf7380d 100644
--- a/notebooks/visualization/src/com/intellij/notebooks/visualization/outputs/impl/NotebookOutputCollapseAllInSelectedCellsAction.kt
+++ b/notebooks/visualization/src/com/intellij/notebooks/visualization/outputs/impl/NotebookOutputCollapseAllInSelectedCellsAction.kt
@@ -39,7 +39,7 @@ internal class NotebookOutputCollapseAllAction private constructor() : ToggleAct
 }
 
 // same as Collapse All Action, but collapse outputs of selected cells
-internal class NotebookOutputCollapseAllInSelectedCellsAction private constructor() : ToggleAction(), DumbAware {
+open class NotebookOutputCollapseAllInSelectedCellsAction() : ToggleAction(), DumbAware {
   override fun getActionUpdateThread(): ActionUpdateThread = ActionUpdateThread.EDT
 
   override fun update(e: AnActionEvent) {