If you add a context menu to a textbox it disables the box. I've asked about this previously in a support call but was told it's not likely to be supported as there's no demand for it. 
  It would allow for excel like interaction where you can select a number of textboxs on mobile and right click/long click to get a menu, 

Since Kendo grid is not a responsive widget, provide a option for users to hide lesser significant columns on smaller screens.

Let user specify the property "HideWhenLessThan" for a column in the grid, which represents the width of the screen below which the column is hidden in the grid. 

Example:
 columns: [{
                            field: "ContactName",
                            title: "Contact Name",
                           HideWhenLessThan: 600
                        }]
                           
Here the column would be hidden when the width of  the grid's parent div or the width of the browser is lesser than 600px.

Need combo with single selection return more than one values. Like country, city, street selection in single control.

https://developers.google.com/maps/documentation/javascript/examples/places-searchbox

Your demos use a very old 1.9.1 version of JQuery.
When we update to later JQuery, this breaks much functionality in KendoUI.
Please make KendoUI work with all versions of JQuery rather than focus on new features. You have versionitis.

It'd be nice if I could this:

<kendo-combo-box k-data-source="flight.airport">
  <span class="k-state-default" k-template>
    <h3>#: data.name #</h3>
    <p>#: data.location #</p>
  </span>
</kendo-combo-box>

We have the need to show master and detail rows in an aligned, tabular format, similar to how the TreeList displays them. Currently, in our grids, we use some "hack" jQuery to achieve this after Kendo renders its child table. (We remove the child rows which kendo rendered in a sub table, place them in the main table right after the parent, and clean up the debris). This is the only way to ensure column alignment, and have re-sizable columns work, etc.

Using the TreeList isn't an option currently, because we want to use some other features of the grid, such as paging and batch editing. There are obviously several more features supported by the grid which don't exist currently in the TreeList.

It would be great if I could simply configure the grid to render detail rows this way.

When the user open with pc or ipad (or bigger screens) then the TabStrip is fine. But when he opens the page with mobile phone its better to have no Tabstrip at all and just have the content pages one after the other with some heading.

Please consider adding feature which implement times series graph similar to "Google Finance stock view".

This will give user multiple zoom options like 10 day, 1 month, 3 month, 6 month, 1 Year and All period.

Then user can see line chart that will reflect user's zoom selection. User can scroll through to see historical data. 

It would be convenient if you could specify the output format using a data attribute such as the following rather than having to write a new viewmodel function:
 
<span data-format="{0:C}" data-bind="text: amount"></span>

Currently you have to bind the element to a new viewmodel function which doesn't lend itself to the observable concept with remote data sources.

I miss being able to preview the mobile widgets in the different themes, could we get a theme switcher for the Hybrid UI demo?

For Kendo UI, it would be great if you could add a kendo configuration to a Model's field which would be used to auto display the html component, here is an example:

var newModel = kendo.data.Model.define({
  id: "id",
  fields: {
    state: {
      type: "string",
      defaultValue: "",
      validation: { required: true },
      component: {
        role: "kendoDropDownList",
        dataSource: {
          data: [
            'Alabama',
            'Alaska',
            'Arizona'
          ]
        }
      }
    }
  }
});

Although Kendo has fency filters with different operators (StartsWith, Contains) on different columns based on data type, Most business users  like to have excel AutoFilter(Multi select checkbox) where they can choose what companies, countries they want to see

You can see a live demo here at - select company, country or any other column.
http://demos.devexpress.com/MVC/GridView/Filtering

You can put multiple inputs in a custom Grid cell editor (textboxes, checkboxes, etc.), but since there's more than 1 and the grid doesn't support binding to arrays/collections out of the box, there's no way to automatically get those values into a model when you move away from the cell. The grid "save" event doesn't fire when there isn't 1 input using "data-bind".
You can put a button or something to click on inside the cell and then in the click event update the model yourself, but that looks odd.
Please add a cell-closing event that allows us to manually update the model or do other clean-up.
OR, please add support for binding to arrays for a field in the grid.
Thanks. 

Kendo UI Tree List control currently does not support column resize and frozen columns. The former prevents us from using it as our end users will not be able to resize the columns when the tree list columns are localized.

Allow the user to resize the editor textarea by dragging the lower right corner. A solution for doing this is given in the forums, but it would be great to have it as built-in functionality.
http://www.kendoui.com/forums/kendo-ui-complete-for-asp-net-mvc/editor/is-it-possible-to-give-the-html-editor-a-resize-grip-.aspx

Provide context menu support for treeview. At least provide mouse click handlers for treeview.
Also how to add items with id from datasource in treeview. You have API to select via item id, but nothing that adds id via datasource.

When window resize , detect all components in it and resize 

When creating a multilingual website I've realized, non-English unicode characters are not supported by the Grid's toolbar buttons. The toolbar won't be created and the Grid's setup cancelled. So, also no read function called or anything else.
Strangely it also killed the functionality of my Razor DropDownList for language selection despite no connection other than both using JavaScript.

Some users prefer larger font sizes than what is default in kendo. We have added an option for setting the default font size in our product, but when we do that some of the widgets brake because they did size calculations on init that is affected by font size changes.

We currently have to reload the entire page as a workaround, but that does not offer the user a smooth experience when changing the font size. At minimum, all widgets should support a resize method that we could trigger such that the widgets could recalculate all required sizes.

Can we have an option where the TabStrip tabs overflow to a dropdown just like the ToolBar items overflow when re-sized instead of wrapping tab items to another line

This would work great on small factor tablets/phones