HTML element is not hidden after deselecting input field

[azbiusta]

I am develoing a mobile webgl game. When using input fields, the plugin automatically opens keyboard and enable me to type into the input field. It also creates an input field element at the bottom of the screen.

The newly created element does not disappear even after deslecting the input field. I tried to modify GetElementRect()

RectInt GetElemetRect()
{
    var rect = input.GetScreenCoordinates();
    // モバイルの場合、強制表示する
    if (showHtmlElement || Application.isMobilePlatform)
    {
        var x = (int)(rect.x);
        var y = (int)(Screen.height - (rect.y + rect.height));
        //return new RectInt(x, y, (int)rect.width, (int)rect.height);
        //return new RectInt(x, y, 0, 0);
        return new RectInt(-9999, -9999, 0, 0);
    }
    else
    {
        var x = (int)(rect.x);
        var y = (int)(Screen.height - (rect.y));
        //return new RectInt(x, y, (int)rect.width, (int)1);
        //return new RectInt(x, y, 0, 0);
        return new RectInt(-9999, -9999, 0, 0);
    }
}

This removed the unwanted html input field, but if I use any input fields, the game becomes unplayable because clicking the buttons at the bottom of the screen selects an invisible input field that I cannot deselect.