Form with browser steals focus from window on top

[assopri]

In my app I create winforms cefsharp browsers outside of the main thread. I use the following code to create form for hosting them (each separate browser is hosted in separate tabpage of tabcontrol in the form):

`private void CreateForm()
{
Form = new Form1( manualResetEvent);
Form.ProceedButtonClicked += (_, browser) =>
{
browserWrapperDictionary[browser].WaitingForUserAction = false;
};

        _thread = new Thread(() =>
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(true);

            while (!_cancellationTokenSource.IsCancellationRequested)
            {
                if (Form.ShowFormFlag) { Form.ShowFormFlag = false; Form.Show(); }
                if (Form.HideFormFlag) { Form.HideFormFlag = false; Form.Hide(); }
                Application.DoEvents();
               
                Thread.Sleep(100);
            }

            Form.Close();
            Form.Dispose();
            
        });

        _thread.SetApartmentState(ApartmentState.STA);
        _thread.Start();
    }`

However I found that when another browser is created form with browser steals focus from my main form and appears to be on top of this form. How can I avoid that?

My OS is Windows7 64x , VS 2019 installed. I use Winforms Cefsharp version, .NET 4.5.2 . Cef version is 90.6.50.0

[amaitland]

However I found that when another browser is created form with browser

Can you clarify what you mean by this?

[assopri]

If I will invest a lot of time in changing my app call hierarchy to use async instead of Wait - how in this case I can use ApplicationContext ? How exactly should I change form creation to use it? https://github.com/assopri/CefSample/blob/210fbf1a5eac73cc0b420a4880ea2f8e1f990741/CefBrowserWrapper/CefBrowserWrapperBase.cs#L153

[amaitland]

how in this case I can use ApplicationContext ? How exactly should I change form creation to use it?

I had a look at your example in detail and you are creating the forms separately, so the ApplicationContext may not be required.

I've reduced your example to the absolute minimum to reproduce the issue https://github.com/amaitland/CefSample/tree/demo/textbox

From what I can tell the problem with form stealing focus is actually related to the TabControl. Switching to a TextBox instead of ChromiumWebBrowser and the problem still occurs.

https://github.com/amaitland/CefSample/blob/demo/textbox/CefBrowserWrapper/BrowserForm.cs#L19

Others are reporting similar issues

• https://stackoverflow.com/questions/3478058/net-winforms-tabcontrol-steals-focus-on-form-activation
• https://www.codeproject.com/Questions/1243997/Winform-tabcontrol-unexpected-focus-change-upon-sw

You can look at the TabControl source via https://referencesource.microsoft.com/#System.Windows.Forms/winforms/Managed/System/WinForms/TabControl.cs
Might give you some clues on how to workaround the issue. Otherwise you just manually refocus your form.

[assopri]

Its awesome! You are completely right! That is about tabcontrol. When I remove changing selected tab "tabControl1.SelectedTab = (browser.Parent as TabPage);" and hiding tabs - focus remains where it must be. However - when avoid selecting tab with active browser I have another issue - webpages (in all browsers except for one in selected tab) - are not loading, so I get timeout exception here:

any workarounds?

p.s. how can I thank you for localization problem with the tabcontrol?

[amaitland]

Sorry for the delayed response, I've been sick most of the last week.

The underlying browser will only be created when the Handle is created. You should be able to set the size of the ChromiumWebBrowser instance and call ChromiumWebBrowser.CreateControl to explicitly load the control.

https://docs.microsoft.com/en-us/dotnet/api/system.windows.forms.control.createcontrol?view=net-5.0

p.s. how can I thank you for localization problem with the tabcontrol?

Your support via GitHub sponsors is sufficient thanks 👍

[assopri]

Hello! I hope you are well!