diff --git a/client/src/components/admin/KontoTable.js b/client/src/components/admin/KontoTable.js
index 27d6a71..176c1c1 100644
--- a/client/src/components/admin/KontoTable.js
+++ b/client/src/components/admin/KontoTable.js
@@ -98,6 +98,12 @@ class KontoTable extends Component {
     });
   };
 
+  isFormValid = () => {
+    const { formData } = this.state;
+    return formData.konto.trim() !== '' && 
+           formData.name.trim() !== '';
+  };
+
   handleSave = async () => {
     const { editingKonto, formData } = this.state;
     
@@ -257,7 +263,11 @@ class KontoTable extends Component {
           </DialogContent>
           <DialogActions>
             <Button onClick={this.handleCloseDialog}>Abbrechen</Button>
-            <Button onClick={this.handleSave} variant="contained">
+            <Button 
+              onClick={this.handleSave} 
+              variant="contained"
+              disabled={!this.isFormValid()}
+            >
               Speichern
             </Button>
           </DialogActions>
diff --git a/client/src/components/admin/KreditorTable.js b/client/src/components/admin/KreditorTable.js
index 7ba85d3..2d19722 100644
--- a/client/src/components/admin/KreditorTable.js
+++ b/client/src/components/admin/KreditorTable.js
@@ -102,6 +102,13 @@ class KreditorTable extends Component {
     });
   };
 
+  isFormValid = () => {
+    const { formData } = this.state;
+    return formData.iban.trim() !== '' && 
+           formData.name.trim() !== '' && 
+           formData.kreditorId.trim() !== '';
+  };
+
   handleSave = async () => {
     const { editingKreditor, formData } = this.state;
     
@@ -270,7 +277,11 @@ class KreditorTable extends Component {
           </DialogContent>
           <DialogActions>
             <Button onClick={this.handleCloseDialog}>Abbrechen</Button>
-            <Button onClick={this.handleSave} variant="contained">
+            <Button 
+              onClick={this.handleSave} 
+              variant="contained"
+              disabled={!this.isFormValid()}
+            >
               Speichern
             </Button>
           </DialogActions>
diff --git a/client/src/components/headers/TextHeaderWithFilter.js b/client/src/components/headers/TextHeaderWithFilter.js
index 50f7318..619ab76 100644
--- a/client/src/components/headers/TextHeaderWithFilter.js
+++ b/client/src/components/headers/TextHeaderWithFilter.js
@@ -290,14 +290,11 @@ export default class TextHeaderWithFilter {
     this.eGui.style.height = '100%';
     this.eGui.style.display = 'flex';
     this.eGui.style.flexDirection = 'column';
-    
-    console.log('TextHeaderWithFilter constructor');
   }
 
   init(params) {
     this.params = params;
-    console.log('TextHeaderWithFilter init params:', params);
-    
+
     // Listen for menu close events to keep state in sync
     if (params.api) {
       params.api.addEventListener('popupMenuVisibleChanged', (event) => {
@@ -312,7 +309,6 @@ export default class TextHeaderWithFilter {
   }
 
   getGui() {
-    console.log('TextHeaderWithFilter getGui called');
     return this.eGui;
   }
 
diff --git a/client/src/components/utils/dataUtils.js b/client/src/components/utils/dataUtils.js
index b5603d9..2d3e323 100644
--- a/client/src/components/utils/dataUtils.js
+++ b/client/src/components/utils/dataUtils.js
@@ -12,9 +12,7 @@ export const processTransactionData = (transactions) => {
 export const getRowStyle = (params, selectedRows) => {
   const rowId = params.data?.id || params.rowIndex;
   const isSelected = selectedRows && selectedRows.has && selectedRows.has(rowId);
-  
-  console.log('getRowStyle called for row:', rowId, 'isSelected:', isSelected, 'selectedRows size:', selectedRows?.size);
-  
+    
   if (params.data.isJTLOnly) {
     return {
       backgroundColor: isSelected ? '#e3f2fd' : '#ffebee',