Thank you for your reply.
Actually, the grid form is my main form. It will be closed only if the user closes the software.
I've add a timer of GC collector in your demo. The refresh timer is triggered every second, the GC timer is triggered every 2 seconds.
sender, EventArgs e)
The memory seems to be leaking more slowly, but there is still a leak.
Please see memory trace in the attached photo.
I don't understand why the memory maintains well only if the master template refreshes. With the hierarchy template, the memory can't stop leaking.
Thank you by advance for your help.