The RadGridView throws unhandled exception, when you try to close the custom filtering form twice for invalid filter descriptor.

1. Create a new project with RadGridView. 

2. Make all columns read only. 

3. Use Ctrl+x, +v and +c key combinations.

1. Create RadGridView with hierarchy.
2. Set UseScrollbarsInHierarchy property to true.
3. Handle the CellDoubleClick event.
4. Run the project, open a child view and double click on its scrollbar. The CellDoubleClick event will fire which is wrong.

To reproduce:
- add a grid to the form and use the following code for its setup:
            radGridView2.Columns.Add("ID");
            radGridView2.Columns.Add("Title");
            radGridView2.MultiSelect = true;
            radGridView2.Columns[0].SortOrder = RadSortOrder.Ascending;
            radGridView2.ReadOnly = true;

            radGridView2.BeginUpdate();
            for (int i = 0; i < 5; i++)
            {
                GridViewDataRowInfo row = new GridViewDataRowInfo(radGridView2.MasterTemplate.MasterViewInfo);
                row.Cells["ID"].Value = i;
                row.Cells["Title"].Value = "Title " + i;
                radGridView2.Rows.Add(row);
            }
            radGridView2.EndUpdate(true);

            radGridView2.Rows[0].IsCurrent = true;
            radGridView2.Rows[0].IsSelected= true;

- Once the application is started, hold down the shift key and click the third row in the grid 

Expected result: the first three rows are selected
Actual result: the last three rows are selected

WORKAROUND:
Use the BeginUpdate and EndUpdate methods of the TableElement, not the control:
radGridView2.TableElement.BeginUpdate();
//add rows
radGridView2.TableElement.EndUpdate(true);

Filtering does not work correctly when NotConains and Contains filters are combined.

Work around:

private void radGridView1_FilterExpressionChanged(object sender, FilterExpressionChangedEventArgs e)
        {
            List<string> filterExpressions = new List<string>();

            for (int i = 0; i < this.radGridView1.FilterDescriptors.Count; i++)
            {
                FilterDescriptor descriptor = this.radGridView1.FilterDescriptors[i];
                string expression = null;

                CompositeFilterDescriptor compositeFilterDescriptor = descriptor as CompositeFilterDescriptor;

                if (compositeFilterDescriptor != null)
                {

                    expression = CompositeFilterDescriptor.GetCompositeExpression(compositeFilterDescriptor);
                }
                else
                {
                    expression = FilterDescriptor.GetExpression(descriptor);
                }

                if (!string.IsNullOrEmpty(expression))
                {
                    filterExpressions.Add("(" + expression + ")");
                }
            }

            string logicalOperator = (this.radGridView1.FilterDescriptors.LogicalOperator == FilterLogicalOperator.And) ? " AND " : " OR ";
            string resultExpression = String.Join(logicalOperator, filterExpressions.ToArray());
            e.FilterExpression = resultExpression;
        }

Export to excel fails when there is null values for GridViewDateTimeColumn.
The following code snippet reproduce the issue:

ExportToExcelML export = new ExportToExcelML(gridView);
export.HiddenColumnOption = HiddenOption.DoNotExport;
export.HiddenRowOption = HiddenOption.DoNotExport;
export.ExportVisualSettings = false;
export.SheetMaxRows = ExcelMaxRows._1048576;
export.RunExport(targetFileName);

This method should return true if successful.

FIX. RadGridViiew - HierarchyLevel property shows incorrect hierarchy level for GridNewRowElement in grid with hierarchy.

The alternating row color in RadGridView does not work when the control is in unbound mode and LoadFrom method is used.

Resolution: 
The issue is duplicated with feedback item FIX. RadGridView - AlternatingRowColor does not work when data is loaded in the RadGridView from a IDataReader
Here is the link to item:  http://feedback.telerik.com/Project/154/Feedback/Details/112656-fix-radgridview-alternatingrowcolor-does-not-work-when-data-is-loaded-in-the-r

Object-hierarchy produces same child rows for every parent row.

If RadDropDownListEditor has DropDown style and you write a value which exists in the underline data source, it does not become current value.

The summary aggregate expression IIF(SUM(RecordCount) = 0, 0, 1/SUM(RecordCount)) causes exception in RadGridView.

The display member for empty string value in GridViewComboBoxColumn is not displayed. The following code reproduces the issue:

GridViewComboBoxColumn cboInsRslCd = new GridViewComboBoxColumn();
cboInsRslCd.DataType = typeof(string);
List<ItemComboBox> liste = new List<ItemComboBox>();
liste.Add(new ItemComboBox("", "[None]"));
liste.Add(new ItemComboBox("A", "A"));
liste.Add(new ItemComboBox("B", "B"));
liste.Add(new ItemComboBox("C", "C"));

cboInsRslCd.DataSource = liste;
cboInsRslCd.ValueMember = "CleItem";
cboInsRslCd.DisplayMember = "ValeurItem";
cboInsRslCd.NullValue = "[None]";
this.radGridView1.Columns.Add(cboInsRslCd);

WORKAROUND:  subscribe to the CellEndEdit event and change the stored value in the event handler:
private void RadGridView1_CellEndEdit(object sender, GridViewCellEventArgs e)
{
    if (e.Value == null)
    {
        e.Row.Cells[e.Column.Name].Value = "";
    }
}

http://www.telerik.com/community/forums/radgridview-comboboxcolumn-displays-no-value-for-member-with-empty-string-value-is-selected

Improve editors in RadGridView by allowing clipping when the control is scrolled.

Column Chooser form's BackColor cannot be set trough Theme.

Steps to reproduce:

1. Addd a numeric (decimal) column to a grid
2. Enable filtering 
3. Select 'Greater Than' filter
4. Enter '0' in the Spin Editor that appears

You will see that no filtering occurs. Enter any other digit instead of 0 and filtering is performed.

Steps to reproduce:
1) Add RadGridView control
2) Add GridViewTextBoxColumn
2) Enable filtering: 

            this.radGridView1.EnableFiltering = true;

3) Programmatically set filter descriptor:

            FilterDescriptor filter = new FilterDescriptor();
            filter.PropertyName = "TextBoxColumn";
            filter.Operator = FilterOperator.IsEqualTo;
            filter.IsFilterEditor = true;
            
            this.radGridView1.FilterDescriptors.Add(filter);

Expected result: the default FilterDescriptor is changed from Contains to IsEqual
Actual result: can not set the default FilterDescriptor from Contains to IsEqual operator to a TextBoxColumn

Workaround:

        private void OnFilterExpressionChanged(object sender, FilterExpressionChangedEventArgs e)
        {
            GridViewTemplate owner = sender as GridViewTemplate;
            List<string> filterExpressions = new List<string>();

            for (int i = 0; i < owner.FilterDescriptors.Count; i++)
            {
                FilterDescriptor descriptor = owner.FilterDescriptors[i];
                string expression = null;

                CompositeFilterDescriptor compositeFilterDescriptor = descriptor as CompositeFilterDescriptor;

                if (compositeFilterDescriptor != null)
                {
                    foreach (FilterDescriptor filterDescriptor in compositeFilterDescriptor.FilterDescriptors)
                    {
                        if (string.IsNullOrEmpty(filterDescriptor.PropertyName) ||
                            owner.Columns[filterDescriptor.PropertyName] == null)
                        {
                            continue;
                        }
                    }

                    expression = CompositeFilterDescriptor.GetCompositeExpression(compositeFilterDescriptor);
                }
                else
                {
                    if (string.IsNullOrEmpty(descriptor.PropertyName) ||
                        owner.Columns[descriptor.PropertyName] == null)
                    {
                        continue;
                    }

                    if (descriptor.Value == null && (descriptor.Operator == FilterOperator.IsNotEqualTo || descriptor.Operator == FilterOperator.IsEqualTo))
                    {
                        expression = string.Empty;
                    }
                    else
                    {
                        expression = descriptor.Expression;
                    }
                }

                if (!string.IsNullOrEmpty(expression))
                {
                    filterExpressions.Add(expression);
                }
            }

            string logicalOperator = (owner.FilterDescriptors.LogicalOperator == FilterLogicalOperator.And) ? " AND " : " OR ";
            string resultExpression = String.Join(logicalOperator, filterExpressions.ToArray());
            e.FilterExpression = resultExpression;
        }

GridView “decimal column -          Current value “500”-          Input “1.2.3.4” Scenario case: 1.       Approaching to the target cell by “Mouse click directly on the input cell” then key in “1.2.3.4” and Enter à Display “500” as original value2.       Approaching to target cell by “Tab or moving cursor to input cell” then key in “1.2.3.4” and Enter à Display “1” as only display the first input digit only

Scrolling when column reorder is performed does not work in hierarchy mode.