[Android] Soft keyboard dismisses and cursor jumps when typing after toggling a mark on a collapsed selection

[virgil1996]

Description
When using Slate on Android. If toggles a mark (e.g., Bold) while the selection is collapsed and then attempts to type, the cursor position breaks and the Android soft keyboard is immediately dismissed. However, if the user highlights an existing piece of text, applies the mark, and then continues typing, the issue does not occur.

I have attached a screen recording demonstrating the exact behavior.

Recording：

20260320-175857.mp4

Steps to reproduce

• Open a Slate editor on an Android
• Focus the editor (Selection must be collapsed).
• Toggle a mark (e.g., Bold).
• Type any character.

Expected behavior：
The soft keyboard should remain open.

Actual behavior：
The soft keyboard is instantly dismissed.

Environment：
OS: Android 16 (Pixel 9a Emulator)

Slate Version: latest？I used the official sample page for testing. https://www.slatejs.org/examples

Keyboard: Default Android Keyboard

[virgil1996]

Add Android example code

<!-- activity_main.xml -->
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <WebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>

// MainActivity.kt

package com.editor.app

import android.annotation.SuppressLint
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.editor.app.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

    @SuppressLint("SetJavaScriptEnabled")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val webView = binding.webView
        webView.settings.apply {
            javaScriptEnabled = true
            domStorageEnabled = true
        }

        webView.loadUrl(SLATE_EXAMPLES_URL)
    }

    companion object {
        private const val SLATE_EXAMPLES_URL = "https://www.slatejs.org/examples"
    }
}

[virgil1996]

apply log:

{
    "type": "insert_node",
    "path": [0, 1],
    "node": { "text": "w", "bold": true }
}

{
    "type": "set_selection",
    "properties": {
        "anchor": { "path": [0,0], "offset": 1 },
        "focus": { "path": [0,0], "offset": 1 }
    },
    "newProperties": {
        "anchor": { "path": [0, 1], "offset": 1 },
        "focus": { "path": [0, 1], "offset": 1 }
    }
}

{
    "type": "set_selection",
    "properties": {
        "anchor": { "path": [0,1], "offset": 1 },
        "focus": { "path": [0,1], "offset": 1 }
    },
    "newProperties": {
        "anchor": { "path": [0, 0], "offset": 1 },
        "focus": { "path": [0, 0], "offset": 1 }
    }
}

{
    "type": "set_selection",
    "properties": {
        "anchor": { "path": [0,0], "offset": 1 },
        "focus": { "path": [0,0], "offset": 1 }
    },
    "newProperties": {
        "anchor": { "path": [0, 1], "offset": 1 },
        "focus": { "path": [0, 1], "offset": 1 }
    }
}

{
    "type": "set_selection",
    "properties": {
        "anchor": { "path": [0,1], "offset": 1 },
        "focus": { "path": [0,1], "offset": 1 }
    },
    "newProperties": {
        "anchor": { "path": [0, 0], "offset": 1 },
        "focus": { "path": [0, 0], "offset": 1 }
    }
}

{
    "type": "set_selection",
    "properties": {
        "anchor": { "path": [0,0], "offset": 2 },
        "focus": { "path": [0,0], "offset": 2 }
    },
    "newProperties": {
        "anchor": { "path": [0, 0], "offset": 0 },
        "focus": { "path": [0, 0], "offset": 0 }
    }
}