ComboBox is set to read-only and can still be edited

### Describe the bug

ComboBox is set to read-only and can still be edited

### Steps to reproduce the bug

<ComboBox IsReadOnly="True" />

### Expected behavior

_No response_

### Screenshots

_No response_

### NuGet package version

HandyControl 3.4.0

### IDE

Visual Studio 2022

### Framework type

.Net 6.0

### Windows version

Windows 11 (22000)

### Additional context

_No response_