Ext JS 6.2.0 Classic how to control the scroll bar Ext.grid.Panel?

The essence - create a simple grid in two columns, fill in some data and get no scroll bar in certain situations.
For example, if the grid to assign the main view - everything is fine. Even if the store receives from the server 3-5 thousand records - nothing slows scrolling dynamically created/removed irrelevant elements of the DOM and everything works fine.

An example in the sandbox https://fiddle.sencha.com/#view/editor&fiddle/2b0h

But if the grid is nested within any panel, you get a very different algorithm - grid created a maximum height - at least 20,000 pixels, this creates all the DOM elements for each entry, not looking three them there or three thousand, there is no scroll bar and everything is decently slow with a large dataset.
to scroll through with only the keyboard by moving the selection in the table, the table header gets up to retrieve it problematic

This can be corrected if the grid to set the height in pixels, but if you try the percent - nothing comes out. But sets the height, in pixels, in the age of adaptive layout is not a decision that we would like.

How to make the grid behave the same way as the main view and in the nested condition?
June 10th 19 at 15:02
1 answer
June 10th 19 at 15:04
and again forum Sencha out of the competition! Helped to solve the issue almost instantly ))
namely, in the section describing the Central panel, which is located a grid it is necessary to register layout: 'fit' and remove explicitly specify the height and width
 items: [{
 xtype: 'clientslist'
 layout: 'fit',

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