Ext 6.5.2 Modern:Very slow load in Safari when empty Grid controls with flex are used

[Nagarjuna.Borra]

Hi,

In Safari browser(iPad/iPhone), a fiddle, which contains two empty grid controls nested under few panels, loads in about 77 seconds, the same fiddle loads in about 2.477 seconds in chrome browser.

Fiddle: https://fiddle.sencha.com/fiddle/2en5/preview (browse the fiddle, notice the "Load Time" text field value)
The Fiddle has below layout(mainContainer, Column, Row, Cell are panels with hbox/vbox layout)
MainContainer
-Columns (columns are horizontally aligned to each other)
-Rows (rows are vertically aligned to each other)
-Cells (cells are horizontally aligned to each other)
-Controls (two empty grid controls, with flex:1)

This is happening only in Safari browser of iPad/IPhone, for the rest of OS/Browser combinations the load time is pretty less.

It appears there are some performance issues with Safari browser when flex boxes are involved(maybe when flex boxes are involved with nested layouts) https://www.reddit.com/r/apple/comme...nce_issues_on/.
There is already a similar post submitted too, https://www.sencha.com/forum/showthr...seriously-slow

I have noticed that this currently happens for grid controls only, if I replace them with buttons or tab item controls then this won't happen (for tab controls, it depends upon the tab items, but still it is not as big as 77 seconds)

This obviously looks like something that needs to be fixed by the Safari webkit, but I am wondering if there is anything we can do from our end? Maybe something that can trim down grid controls? (If any), just checking the possibility.

Thank you,
Nagarjuna

[evant]

http://docs.sencha.com/extjs/6.5.3/m...l#cfg-autoSize

[Nagarjuna.Borra]

I have placed an override that would set all containers to have autoSize:false (same fiddle posted in the Question),

Ext.override(Ext.Container, {
    autoSize: false,
});

but could not see any reduction in the lag!!.

[evant]

Read the docs:

Ext.define('MyApp.overrides.Container', {
    override: 'Ext.Container',
    config: {
        autoSize: false
    }
});

[Nagarjuna.Borra]

Many thanks, with the override the fiddle now loads within 2s!..
(I thought Ext.override({ overrides }) is just as same as Ext.define(override: { overrides } !!)