We are experiencing a significant issue with the latest version of Telerik components for WinForms.
The RadTreeView control is affected.
The tree view is populated with nodes.
When nodes are expanded and then scrolled, the +/- indicators are no longer displayed correctly and the elements are also no longer displayed correctly. It even goes so far that no elements are displayed at all (only the root element always seems to remain).

It happens only on environments that we access by remote desktop connection. Never on the local environment till now.

There is a big problem with Telerik controls when using national resource files.  Switching from one language to another and again sometimes destroys the user interface. It especially concerns RadCheckBox control. Text, tooltip and probably other properties from one control appear in other control etc. I think it can be a general problem because I also noticed that sometimes Image from one RadButton control appears in other button.

I prepared a set of images which show how it happended in my case. Switching from Default language to Polish language and again and then adding and removing new RadCheckBox completly destroyed user interface in my sample UserControl. This new RadCheckbox was created as a copy of existing RadCheckBox what may be a clue.

I also attached VS2019 project with my sample UserControl.

Best regards,

Andrzej

Repro-steps:

1. Use the code beneath.
2. Run this form.
3. 20 records are shown, the "AddNewRow" is shown.
4. Select all records.
5. Press <delete>
6. 0 records are shown (as expected), the "AddNewRow" is invisible (unexpected).
7. Close the program.
8. Modify LoadTable(true) to LoadTable(false). Records will not be created..
9. Run this form.
10. 0 records are shown (as expected), the "AddNewRow" is invisible (unexpected).

Expected behavior:

• Even when the dataTable or view has no rows, we should still be able to add new rows.

Observed behavior:

• When datatable/view is empty, no new records are allowed to enter.

Please observe that Grid.UserAddedRow is not handled, but since we cannot even see the AddNewRow, it is not required for this bug.

	public partial class TestForm: Form
	{
		private readonly DataView _view;

		public TestForm()
		{
			InitializeComponent();

			_view = new DataView(LoadTable(true));
			_grid.ColumnCount = _view.Table.Columns.Count;
			_grid.RowCount = _view.Count;
			_grid.AllowAddNewRow = true;
			_grid.SelectionMode = VirtualGridSelectionMode.FullRowSelect;
		}

		static private DataTable LoadTable(bool fill)
		{
			var table = new DataTable();
			table.Columns.Add("Number", typeof(int));
			
			if (fill)
				for(int i = 0; i < 20; i++)
					table.Rows.Add(i);
			
			return table;
		}


		#region Windows Form Designer generated code

		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this._grid = new Telerik.WinControls.UI.RadVirtualGrid();
			((System.ComponentModel.ISupportInitialize)(this._grid)).BeginInit();
			this.SuspendLayout();
			// 
			// _grid
			// 
			this._grid.Dock = System.Windows.Forms.DockStyle.Fill;
			this._grid.Location = new System.Drawing.Point(0, 0);
			this._grid.MultiSelect = true;
			this._grid.Name = "_grid";
			this._grid.SelectionMode = Telerik.WinControls.UI.VirtualGridSelectionMode.FullRowSelect;
			this._grid.Size = new System.Drawing.Size(800, 450);
			this._grid.TabIndex = 0;
			this._grid.CellValueNeeded += new Telerik.WinControls.UI.VirtualGridCellValueNeededEventHandler(this._grid_CellValueNeeded);
			this._grid.UserDeletedRow += new Telerik.WinControls.UI.VirtualGridRowsEventHandler(this._grid_UserDeletedRow);
			// 
			// TestForm
			// 
			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
			this.ClientSize = new System.Drawing.Size(800, 450);
			this.Controls.Add(this._grid);
			this.Name = "TestForm";
			this.Text = "TestForm";
			((System.ComponentModel.ISupportInitialize)(this._grid)).EndInit();
			this.ResumeLayout(false);

		}

		#endregion

		private Telerik.WinControls.UI.RadVirtualGrid _grid;

		private void _grid_CellValueNeeded(object sender, Telerik.WinControls.UI.VirtualGridCellValueNeededEventArgs e)
		{
			if (e.ColumnIndex < 0)
				return;

			if (e.RowIndex < 0)
			{
				e.FieldName = _view.Table.Columns[e.ColumnIndex].ColumnName;
				if (e.RowIndex == RadVirtualGrid.HeaderRowIndex)
					e.Value = e.FieldName;
			}
			else if (e.RowIndex < _view.Count)
			{
				e.Value = _view[e.RowIndex][e.ColumnIndex];
			}
		}

		private void _grid_UserDeletedRow(object sender, Telerik.WinControls.UI.VirtualGridRowsEventArgs e)
		{
			var rowIndexes = e.RowIndices.Distinct().OrderByDescending(i => i).ToList(); // Off topic: I have seen duplicate row indexes in this row collection. And unsorted. Is that by design?
			if (rowIndexes.Count == _view.Count)
			{
				_view.Table.Rows.Clear();
			}
			else
			{
				foreach(var index in rowIndexes)
					_view[index].Delete();
			}

			_grid.RowCount = _view.Count;
		}
	}

In the following case, we have a document with hyperlinks that scroll to a specific location in the document. Clicking on the links does not scroll to the specified location.

The content is exported correctly, but the following error occurs:

I want to choose columns by checkboxes, something like this:

I might be missing something, but I have Hyperlinks in a column in my RadDatGridView.

I tried searching for a Support document explaining this, but didn't find any.

When the grid is exported to excel all data is coming across, but the column with hyperlink is not

a hyperlink in Excel.

Below is sample of the code used to make the "HyperLink" column in my grid.

                radGridView1.DataSource = dtResults;
                radGridView1.Columns.Remove("Path");
                GridViewHyperlinkColumn col = new GridViewHyperlinkColumn();
                radGridView1.Columns.Insert(5, col);
                col.Width = 200;
                col.FieldName = "Path";
                col.HeaderText = "Path";
                col.Name = "Path";

Coded used to do the Export....

               GridViewSpreadExport spreadExporter = new GridViewSpreadExport(this.radGridView1);
                spreadExporter.ExportVisualSettings = true;
                SpreadExportRenderer exportRenderer = new SpreadExportRenderer();

                spreadExporter.RunExport(filename, exportRenderer);

Thanks.

Roger

It used to work until Q3 2024:

After that, the import operation is successful. However, the image rendering of the SVG when assigning the Workbook results in an error message:  System.ArgumentException: 'Parameter is not valid.'

        public Form1()
        {
            InitializeComponent();
            using (var fileStream = File.OpenRead("example.xlsx"))
            {
                Workbook wb = new XlsxFormatProvider().Import(fileStream);
                radSpreadsheet.Workbook = wb;
            }
        }

To reproduce:
public Form1()
{
    InitializeComponent();

    this.radTextBox1.Text = "abcd";
    this.radTextBox2.Text = "abcd";
    this.radTextBoxControl1.Text = "abcd";
    this.radTextBoxControl2.Text = "abcd";

    this.radTextBox2.Multiline = true;
    this.radTextBoxControl2.Multiline = true;

    this.textBox1.Text= "abcd";
    this.textBox2.Text= "abcd";
    this.textBox2.Multiline = true;
}

Workaround: set the Multiline property to true in the Form.Load event.

Second workaround: this.radTextBox2.TextBoxElement.TextBoxItem.Margin = new Padding(-2, 0, 0, 0);

To reproduce:
this.radTextBoxControl1.Text = "dog and blue glue";
this.radTextBoxControl1.Size = new Size(50, 65);
this.radTextBoxControl1.Multiline = true;

Workaround:
use RadTextBox.

1. Add RadDropDowlList in form. 
2. Open the items collection and add some items. 
3. After that set the Selected property of one item to true and click OK. 
4. You will see that the change is not saved.

Workaround: 
Set the selected item at run time.

Team,

we did not get any help from public forum,

we are expecting in 2026 Q1,

RadControl: Incorrect Font scaling after DPI switch runtime

team,

we did not get any help from public forum,

already we commited our stack holders will resolve in 2026 Q1, so please close ASAP.

RadControl: Incorrect Font scaling after DPI switch runtime