The grid has a number of built in filters, what is not supported is searching for cells that have no value or some value (i.e. NULL or NOT NULL).
This would be a very useful addition.

I'd like to see an event for Grid contents modified (after-edit or after-add/delete, etc).  This would enable a sync with a DataSource, for instance, without further user action.  Presently, this is not easily achieved.

It should be possible to change the width of a grid after it created.
http://www.telerik.com/forums/change-column-widths-after-grid-created

Add Min Width Property to Grid Column so that a user can't manually shrink a column beyond a certain width.

Ability for a grid to show foreign key values from a remote datasource rather than just a fixed array.

Refer to: http://www.kendoui.com/forums/ui/grid/foreign-key-option-doesn-t-work.aspx

The event args from column.groupHeaderTemplate (and groupFooterTemplate) should contain a function to retrieve the data for that group. Currently, they only contain "field" and "value." If you made the grouped rows available in this event, clients would be free to add multiple aggregate columns of the same type (i.e., get the "sum" of multiple values instead of being limited to a single value). I've been able to halfway implement this, but it only works correctly if I'm only grouping by one column. For example, if I'm grouped by WidgetName and then by ProductCode, my event args for ProductCode should contain a function to return data rows for only rows matching the current ProductCode and WidgetName.

Currently we do not have the ability for descending to be first. It's either one, both in the asc/desc order, or none. You can changed the setting in the kendo javascript file but it'd be useful to have it be a property.

http://www.kendoui.com/forums/ui/grid/pager-controls-should-be-hidden-when-total-results-is-less-than-the-pagesize.aspx

Right now there are two options for sorting, single and multi-column. We would very much like to use the multisort version, however our users fail to understand the functionality. We suggest a new setting, "ctrl-multisort":

Single-sort when clicking and multi-sort when ctrl-clicking, similair to most desktop grid controls.

Excel-like filter always show all available options.
When one filter was already applied  - could we limit number of options to see only options that are left after previous filtration?

We should be able to filter only by already filtered rows.

As alternative - could we have some event on Excel-like filter to populate options for it every time it expands?

Currently we use batch editing in the Grid control. The idea of batch editing is all changes are retained client side until the user presses the save button. 

When editing a cell a red dirty indicator is placed on the cell. This gives the user an indication that there are unsaved changes. however, when deleting a row, the row just goes away. There is no indication the user must still save. 

I would like to see rather than the record immediately removed a class applied to the row so we can apply some style like a strikethrough or red background color to indicate a pending delete. Also, we would be able to switch the "delete" button to an "undo" button.

Currently Kendo UI grid don't have any way to know that grid changes its mode from edit to view in case of incell editing.
As per thread (http://www.telerik.com/forums/is-there-any-way-to-know-grid-edit-mode-changes) we have to add blur/focusout event handler to know changing mode. But some time it happen (in case of adding custom widgets through columns editor) that blur/focusout event triggered but still grid is in edit mode.
Its better to have an event when grid changes its mode from edit to view so that we can minimize issue mentioned above.

Currently if you add a row to a grid in batch edit mode any rows that have already been edited will lose their dirty flag indicator.  I would like for Kendo to handle maintaining the dirty flag for these rows.  If there is a performance concern with adding this functionality, then maybe there could be a setting to turn it on or off.

include checkbox-based selection in the grid and allow the persisting of selections in paginated grid (i.e. user selects rows on page 1, switches to page 2, returns to page 1 --> previous selection is restored)

Very often in grids we want command buttons disabled (or not even visible) depending upon model data, such as Delete not being available if the data has certain values set. Something like:

columns.Command(commands => {
  commands.Edit();
  commands.Destroy().VisibleIf(model => model.IsPosted)
  });

Using HtmlAttributes would be acceptable if it was easy to access the model. I'm currently achieving this by using a client template and rendering the buttons myself, but this seems overly complex for what is a simple occurance.

Allow customisation of the bool filter in grids.  I.E. implement the UI property that works for other non-checked columns.  The current filter is too wide, does not allow fontawesome characters, etc.

I was working with Sencha ExtJS and they have to option to make components "stateful" (http://docs.sencha.com/extjs/6.2.0/classic/Ext.state.Provider.html). This will safe user modified settings in browser (defaults to cookie but you can provide your own implementation).

Example (for grid):
* we specify width=100 for first colum
* we allow users to resize columns
* If a users resizes a column the new width will be stored in state
* ... if the user later opens the page again, values from state will overwrite "defaults" from code.

If we use this for column width, visibility and order we've a perfect customizable grid view.

When you configure a grid date-column with a custom format, the value configured in 'format' is parsed using JSON.parse. This requires the use of double quotes for both keys and values.

var a = "{0:dd/MMMM/yyyy}";    // example from docs
JSON.parse(a);    // SyntaxError: JSON.parse: expected property name or '}'

var b = '{"0":"dd-MM-yyyy"}';
JSON.parse(b);    // jey! 

However, if you use the latter, the generated template goes fubar with the message:

"Invalid template:' ... <td>${kendo.format("{"0":"dd-MM-yyyy"\}",theDataField)}</td> ... "

This makes sense when you look at the quote mismatch..

Add the ability to display the Show/Hide Column menu by right clicking the Column Header instead of going through the "Column Menu".

It would also be nice if you could access the Filter directly instead of going through the "Column Menu"

The current Column Menu unnecessarily hides functionality in a menu  that should be more easily accessible.

When I bind a change event to the grid it will fire each time I click on the row, even if it is the same row.  So the selected row is not actually changing, but the event keeps firing anyways.  The same thing happens if I programmatically select the row using the select method.

I would rather the change event only fire when when the selection has actually changed rather than on every re-selection.

Otherwise, you might as well call the event "onSelect" rather than "change".

For extra points, it would be cool if the event received a reference to the previous row that was selected.