Hello Naveen,

Thank you for your feedback. Your issue has been reported as a bug and you can follow its public thread on this link: https://feedback.telerik.com/kendo-jquery-ui/1402793

The bug is being reproduced in the following scenarios:

• If you select a column and while holding the mouse button clicked you move the mouse cursor over a range of merged cells.
• If the merged cells range is on row 1, the selection will not work if you move the mouse cursor both over the range of merged cells and the columns' headings of the merged cells

To continue your regular work with SpreadSheet you can select the columns you need by selecting the first column, holding the mouse clicked and moving the cursor aside but not over the column's headings or over the merged cells range. For example, you can select a column and when trying to select its neighbor do it the way you know it but move the cursor below the merged cells range. 

Another way to select desired columns is to hold the CTRL button and click on the headings of the columns you want to select. 

Thank you once again for posting about this issue. 

I've updated your Telerik points as a sign of gratitude. 

Regards,