Why hotkeys stop working and how to fix it?

Question

.NET

There is a .NET form that is called in 3ds max.
Sometimes, after opening the TollStripSplitButton dropdown list in 3ds max, hotkeys stop working.
It is treated by right-clicking (it looks like you need to open any other menu) either in the 3ds max window itself, or on the form itself.
Here is such a mystic.
Any ideas how to fix the situation?
Thank you.

Answer 1

So far I have decided with a similar crutch

public class ToolStripSplitButtonEx : ToolStripSplitButton
    {
        protected override void OnDropDownClosed(EventArgs e)
        {
            base.OnDropDownClosed(e);
            if (DropDown != null)
                DropDown.Close();
        }
    }

Answer 2

Hotkeys can stop due to a change in layout or due to the focus moving to another window.