setFontSize doesn't work when using soft keyboard

[Foolment]

Describe the bug
After calling RoosterApi.setFontSize() without selecting any text, typing something but the font size didn't get changed.
It only happens when using the soft keyboard to input.

To Reproduce

1. Open RoosterJs Demo Site in browser app (Edge, Chrome) with an Android phone.
2. Tab on the increase font size button several times.
3. Input something by soft keyboard.
4. Check the font size whether it's correct.

Expected behavior
The font size should get changed

Screenshots
Screen recording:
https://github.com/microsoft/roosterjs/assets/3321518/64f4b94b-38aa-4348-b60d-11451d27e6de
The first hello I inputed by physical keyboard, DOM result:

The second hello I inputed by soft keyboard, DOM result:

Device Information

• OS: Android
• Browser: Edge, Chrome

[JiuqingSong]

Thanks for reporting.

Can you help me check from https://microsoft.github.io/roosterjs/index.html#event, when use soft keyboard on Android, what events are fired? I tried on Windows but everything works well, so not sure for Android.

[Foolment]

Physical keyboard	Soft keyboard

Looks like there is one more KeyPress event of each typing when using physical keyboard.

[JiuqingSong]

Can you debug if it can hit the code below (packages\roosterjs-editor-core\lib\corePlugins\PendingFormatStatePlugin.ts) in and if it working correctly when press a key?

Also, can you try content model editor (https://microsoft.github.io/roosterjs/index.html?cm=1) see if the same scenario is working well in Android.

[Foolment]

Thanks for sharing the related code, which allow us to see clearly about this issue now.
I put some log to into code, and when I input a character by physical keyboard, everything is ok since we can receive the character correctly by event.rawEvent.key:

But when I input the same character by soft keyboard on the Android platform, we receive Unidentified and stop us from inserting the node with style later.

For the unidentified key issue, I raised a related issue before: Space key doesn't trigger the auto link feature in Android WebView
This is a platform compatibility issue (or their "design"), but I remember that setFontSize() was working properly at the old time, like one year ago.

Some workarounds/articles might help:

1. Input on Android: 229 Unidentified
2. Issue 935275: keyEvent codes are "Unidentified" with virtual keyboard

[JiuqingSong]

Thanks. Can you try if the Content Model editor works? https://microsoft.github.io/roosterjs/index.html?cm=1 It is using Input event instead.

[Foolment]

It's weirder when testing in content model editor. The increase font size button didn't work either.
Two screenshots attached,
content-model-increase-font-size.mp4
content-model-set-font-size.mp4

Working on debugging the code when using Content Model, will circle back later