webbrowser cannot use input method

Development Programming & Scripting C++
1

I create a UMG with a webbrowser, add to viewport, I get it load url “www.baidu.com”, and I want to input some chinese characters at textbox, but I cannot use input method, anyone hnows this issue? thanks.

my unreal version is 4.15; platform is win10.

2 
/**** File UFoxWebBrowser.h ****/

#pragma once

#include "CoreMinimal.h"
#include "WebBrowser.h"
#include "FoxWebBrowser.generated.h"

/**
 * My Custom Web Browser
 */
UCLASS()
class UFoxWebBrowser : public UWebBrowser
{
	GENERATED_BODY()

public:

	/**
	 * Set input method enable/disable
	 */
	UFUNCTION(BlueprintCallable, Category = "Web Browser")
	void SetInputEnable(bool bEnable) const;
};

/**** File UFoxWebBrowser.cpp ****/

void UFoxWebBrowser ::SetInputEnable(bool bEnable) const
{
	if (!WebBrowserWidget.IsValid())
	{
		UE_LOG(LogTemp, Warning, TEXT("WebBrowserWidget is not init."));
		return;
	}

	if (bEnable)
	{
		if (ITextInputMethodSystem* const TextInputMethodSystem = 
                	FSlateApplicationBase::Get()
                		.GetPlatformApplication()
                		->GetTextInputMethodSystem())
		{
			// The input method will enable to web browser
			WebBrowserWidget->BindInputMethodSystem(TextInputMethodSystem);
		}
	}
	else
	{
		// The input method will disable to web browser
		WebBrowserWidget->UnbindInputMethodSystem();
	}
}