I have a telerik grid which uses inline editing.
Something I found it does which is quite annoying is when I start editing a row some of the columns resizes, the delete button dissapears and a ‘cancel’ button appears next to the edit button in the edit buttons column.
This is what it looks like:

This is how the grid is being created:
<%
Html.Telerik().Grid<myapp.Date>("dates")
.Name("MyGrid")
.Pageable()
.Sortable()
.Filterable()
.Groupable()
.DataKeys(keys => keys.Add(c => c.id))
.DataBinding(dataBinding =>
{
dataBinding.Ajax()
.Select("_SelectAjaxEditing", "Dates")
.Insert("_InsertAjaxEditing", "Dates")
.Update("_SaveAjaxEditing", "Dates")
.Delete("_DeleteAjaxEditing", "Dates");
})
.ToolBar(commands => commands.Insert())
.Columns(columns =>
{
columns.Bound(o => o.name);
columns.Bound(o => o.date1);
columns.Command(commands => commands.Edit());
columns.Command(commands=> commands.Delete());
})
.Editable(editing => editing.Mode(GridEditMode.InLine))
.Render();
%>
It is the normal way how Telerik Grid behaves.
You can make those columns hidden, if don’t need them.
Or may be you can try to use InCell edit mode.