Reproduction: https://blazorrepl.telerik.com/QJEJlAvY33zlToJO18.

To reproduce:

step 1: observe that cells div.k-spreadsheet-fixed-container fills div.k-spreadsheet-view
step 2: Move the splitter handler to left
step 3: Observe that the div.k-spreadsheet-view width is adjusted to the new size of its parent, but div.k-spreadsheet-fixed-container is not.

Expected:  Spreadsheet component handles updating the size its parts.

===

ADMIN EDIT

===

A possible workaround for the time being is to simulate the browser resize event - the Spreadsheet is properly resized in this case. 

Here is how to achieve that: https://blazorrepl.telerik.com/wzOfQbEW38JtEjFD36.