Update control.ts

[Debenben]

fix Uncaught TypeError: Cannot read properties of undefined (reading 'getScene')

When trying to use BabylonJS version 7.6.0 or later I get a crash, I believe this proposed change should fix it, if there is more to it let me know and I can share the complete setup to reproduce the crash.

[bjsplat]

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[bjsplat]

Snapshot stored with reference name:
refs/pull/15116/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15116/merge/index.html

To test a playground add it to the URL, for example:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15116/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/15116/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/15116/merge
https://gui.babylonjs.com/?snapshot=refs/pull/15116/merge
https://nme.babylonjs.com/?snapshot=refs/pull/15116/merge

To test the snapshot in the playground with a playground ID add it after the snapshot query string:

https://playground.babylonjs.com/?snapshot=refs/pull/15116/merge#BCU1XR#0

[bjsplat]

WebGL2 visualization test reporter:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15116/merge/testResults/webgl2playwright/index.html

[bjsplat]

Visualization tests for WebGPU (Experimental)
Important - these might fail sporadically. This is an optional test.

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15116/merge/testResults/webgpuplaywright/index.html

[deltakosh]

How do you repro the issue?

I have no problem with that fix but curious to see how it can happen

[Debenben]

The crash can be reproduced like this:

    var advancedTexture = BABYLON.GUI.AdvancedDynamicTexture.CreateFullscreenUI("ui");
    var control = new BABYLON.GUI.TextBlock("control");
    var panel1 = new BABYLON.GUI.StackPanel("panel1");
    panel1.addControl(control);
    advancedTexture.addControl(panel1);
    var panel2 = new BABYLON.GUI.StackPanel("panel2");
    //panel1 is added to texture, but not panel2
    panel2.addControl(control); // <-- crashes here

In my code I needed to rearrange controls in a stackpanel. There are probably better ways to do this, but at the time I used a temporary stack panel here:
https://github.com/Debenben/babyele/blob/master/src/guimodeselection.ts#L206