RichTextBox lose color during float about dockpanelsuite HOT 4 OPEN

/*
 * Copyright (c) 2022 Christopher Hayes
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
using System;
using System.Windows.Forms;

namespace TheBlackRoom.WinForms.Controls
{
    /// <summary>
    /// RichTextBox with workarounds for:
    ///     setting ZoomFactor
    ///     losing ZoomFactor on clear
    ///     losing RTF colourtable and formatting on font change or parent font change
    /// </summary>
    public class RichTextBoxEx : RichTextBox
    {
        protected override void OnFontChanged(EventArgs e)
        {
            //HACK: save the RTF as changing the font (or having the parent form's font change)
            //      causes the RTF to lose colour and formatting
            var savedRTF = this.Rtf;
            var savedSelectionStart = this.SelectionStart;
            var savedSelectionLength = this.SelectionLength;

            //HACK: save the zoom factor as setting the RTF sets it back to 1
            var tmpZoomFactor = this.ZoomFactor;

            //this line here causes the formatting loss
            base.OnFontChanged(e);

            //reset to the saved RTF
            this.Rtf = savedRTF;

            //Changing the RTF resets the zoom factor back to 1
            this.ZoomFactor = tmpZoomFactor;

            //Restore selection
            this.SelectionStart = savedSelectionStart;
            this.SelectionLength = savedSelectionLength;

            //Restore scroll position
            this.ScrollToCaret();
        }

        public new float ZoomFactor
        {
            get { return base.ZoomFactor; }
            set
            {
                //HACK: in order to properly set the zoom factor, set it twice.
                //      sometimes the underlying zoomfactor changes but the property
                //      doesn't.
                base.ZoomFactor = 1.0f;
                base.ZoomFactor = value;
            }
        }

        public new void Clear()
        {
            //HACK: save and restore the zoom factor as Clear()
            //      resets the zoom factor back to 1
            var tmpZoomFactor = ZoomFactor;

            base.Clear();

            ZoomFactor = tmpZoomFactor;
        }
    }
}

/*
 * Copyright (c) 2022 Christopher Hayes
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
using System.Windows.Forms;

namespace TheBlackRoom.WinForms.Controls
{
    public static class RichTextBoxExtensions
    {
        public static void AppendRtf(this RichTextBox richTextBox, string Rtf)
        {
            if (string.IsNullOrEmpty(Rtf))
                return;

            //put selection at the end of the text
            richTextBox.Select(richTextBox.TextLength, 0);

            //Append rtf text
            richTextBox.SelectedRtf += Rtf;

            //put selection at the end of the text
            richTextBox.Select(richTextBox.TextLength, 0);
        }
    }
}