diff --git a/src/gui_qt/data/datawidget/datawidget.py b/src/gui_qt/data/datawidget/datawidget.py
index 01c30a2..28dc1c1 100644
--- a/src/gui_qt/data/datawidget/datawidget.py
+++ b/src/gui_qt/data/datawidget/datawidget.py
@@ -84,7 +84,7 @@ class DataTree(QtWidgets.QTreeWidget):
         self.update_indexes()
 
     @QtCore.pyqtSlot(QtWidgets.QTreeWidgetItem)
-    def data_change(self, item: QtWidgets.QTreeWidgetItem) -> tuple[set, set]:
+    def data_change(self, item: QtWidgets.QTreeWidgetItem, emit: bool = True) -> tuple[set, set]:
         idd = item.data(0, QtCore.Qt.UserRole)
         is_selected = item.checkState(0) == QtCore.Qt.Checked
         to_be_hidden = set()
@@ -142,9 +142,10 @@ class DataTree(QtWidgets.QTreeWidget):
                         pass
 
             else:
-                self.keyChanged.emit(idd, item.text(0))
+                if emit:
+                    self.keyChanged.emit(idd, item.text(0))
 
-        if to_be_shown or to_be_hidden:
+        if (to_be_shown or to_be_hidden) and emit:
             self.stateChanged.emit(list(to_be_shown), list(to_be_hidden))
 
         return to_be_shown, to_be_hidden
@@ -316,26 +317,24 @@ class DataTree(QtWidgets.QTreeWidget):
                 if idx.column() != 0:
                     continue
                 item = self.itemFromIndex(idx)
-
                 if item.parent() is None:
-                    is_selected = item.checkState(0)
-                    self.blockSignals(True)
                     for i in range(item.childCount()):
                         child = item.child(i)
                         from_parent.append(child)
-                    self.blockSignals(False)
-                    if is_selected == QtCore.Qt.Checked:
-                        item.setCheckState(0, QtCore.Qt.Unchecked)
-                    else:
-                        item.setCheckState(0, QtCore.Qt.Checked)
-
-                else:
-                    sets.append(item)
+                sets.append(item)
 
+            to_be_hidden = set()
+            to_be_shown = set()
+            self.blockSignals(True)
             for it in sets:
                 if it in from_parent:
                     continue
                 it.setCheckState(0, QtCore.Qt.Unchecked if it.checkState(0) == QtCore.Qt.Checked else QtCore.Qt.Checked)
+                s1, s2 = self.data_change(it, emit=False)
+                to_be_hidden |= s2
+                to_be_shown |= s1
+            self.blockSignals(False)
+            self.stateChanged.emit(list(to_be_shown), list(to_be_hidden))
         else:
             super().keyPressEvent(evt)
 
diff --git a/src/gui_qt/graphs/graphwindow.py b/src/gui_qt/graphs/graphwindow.py
index ad6755f..6d7eb16 100644
--- a/src/gui_qt/graphs/graphwindow.py
+++ b/src/gui_qt/graphs/graphwindow.py
@@ -177,9 +177,9 @@ class QGraphWindow(QtWidgets.QGraphicsView, Ui_GraphWindow):
         if isinstance(name, str):
             name = [name]
             plots = [plots]
-
+        toplevel = len(self.sets)
+        self.listWidget.blockSignals(True)
         for (real_plot, imag_plot, err_plot), n in zip(plots, name):
-            toplevel = len(self.sets)
             self.sets.append(n)
 
             if real_plot:
@@ -199,7 +199,16 @@ class QGraphWindow(QtWidgets.QGraphicsView, Ui_GraphWindow):
             list_item.setCheckState(QtCore.Qt.Checked)
             self.listWidget.addItem(list_item)
 
-        self.show_item(name)
+            toplevel += 1
+        self.listWidget.blockSignals(False)
+
+        if len(name) < 200:
+            self.show_item(name)
+        else:
+            QtWidgets.QMessageBox.warning(self, 'Display disabled',
+                                          'If more than 200 sets are added at once, they are not displayed to avoid major performance issues.\n'
+                                          'Building the data tree may still take some time, the checkmark on the left is invalid.\n'
+                                          'Please display them manually in smaller batches, thank you!')
 
     def remove(self, name: str | list):
         if isinstance(name, str):
diff --git a/src/gui_qt/main/management.py b/src/gui_qt/main/management.py
index ca5b065..4e6a09e 100644
--- a/src/gui_qt/main/management.py
+++ b/src/gui_qt/main/management.py
@@ -385,12 +385,16 @@ class UpperManagement(QtCore.QObject):
 
     def change_visibility(self, selected: list, deselected: list):
         """Change status of list of ids after status change in datawidget"""
+        for item_list, func in [(selected, 'show_item'), (deselected, 'hide_item')]:
+            grouping = {}
+            for s in item_list:
+                g = self.data[s].graph
+                if g not in grouping:
+                    grouping[g] = []
+                grouping[g].append(s)
 
-        for s in selected:
-            self.graphs[self.data[s].graph].show_item([s])
-
-        for d in deselected:
-            self.graphs[self.data[d].graph].hide_item([d])
+            for k, v in grouping.items():
+                getattr(self.graphs[k], func)(v)
 
     @QtCore.pyqtSlot(str, str)
     def change_keys(self, identifier: str, name: str):
diff --git a/src/nmreval/io/hdfreader.py b/src/nmreval/io/hdfreader.py
index 8c681ce..f3fe96e 100644
--- a/src/nmreval/io/hdfreader.py
+++ b/src/nmreval/io/hdfreader.py
@@ -134,8 +134,8 @@ class HdfNode:
         else:
             self.parameter[key] = value
 
-        if self.parent is not None:
-            self.parent.set_parameter(key, value, keep=True)
+        # if self.parent is not None:
+        #     self.parent.set_parameter(key, value, keep=True)
 
     def set_title_parameter(self, child_node, params):
         if params:
@@ -174,7 +174,7 @@ class HdfReader(HdfNode):
                     self.create_node(self.file[base], parent=self)
             except OSError:
                 self.file = None
-                raise IOError('Invalid file ' + filename)
+                raise IOError(f'Invalid file {filename}')
 
     def __call__(self, filename, base='data_pool'):
         super().clear()
@@ -215,6 +215,7 @@ class HdfReader(HdfNode):
                     parent[name] = data
                     parent.num_signals += 1
 
+                    # searching for attributes is performance bottleneck but necessary
                     for desc in attr.keys():
                         # looking for description_KEY in attributes
                         m = re.search(r'description_(?P<var>\S+)', desc)