Winforms: ContextMenuStrip not opening when moving window on secondary display

[ccornici]

• .NET Core Version: 3.1
  

• Have you experienced this same bug with .NET Framework?: Haven't tried. I need to use .NET Core
  

Problem description:
Given

• a WPF app
• that uses the WinForms ContextMenuStrip
• in a dual monitor setup
• when moving the MainWindow to the secondary monitor
• the context menu does not display at all

Expected behavior:
The context menu is displayed

Minimal repro:
Repo: https://github.com/ccornici/tray_context_menu_bug

Demo (contained in the repo too)

Other details:

• All other tray icons from other apps (ex: Spotify, NVidia Control Panel etc) work as expected. So it doesn't look like a WIn 10 bug that affects any and all tray icons.
• The Opening event of the ContextMenuStrip gets fired. It simply doesn't display the context menu...

[merriemcgaw]

@Olina-Zhang can you check out this scenario without WPF involved - just the NotifyIcon scenario on multi-monitor setups?

[Olina-Zhang]

@Olina-Zhang can you check out this scenario without WPF involved - just the NotifyIcon scenario on multi-monitor setups?

I can repro this issue in our both Winforms .Net Core and .Net framework app on multi-monitor setups: when form moves to secondary screen, the binding menuContextStrip for notifyIcon cannot be shown.
.Net Core app:
WindowsFormsCore.zip
.Net framework app:
WindowsFormsApp6.zip

[ccornici]

Is there any plan to fix this?...

[RussKie]

Given the issue has always been there since .NET framework, this issue has a lower priority for the team. Adding to the .NET 6.0 milestone but no hard commitment.
We will gladly accept pull-requests with a fix.

The issue will not be fixed in .NET Framework as it won't meet the servicing bar.

[OlegRa]

I've made some research on it (one of my clients has a similar issue with a simple .NET Core 3.1 WinForms application). If you have 2 or more monitors with the same DPI settings all work fine but if DPI values for the screen with notification area and main application window screen are different context menu will not be visible. I'll try to figure out the root cause.