Text entry not possible after failed login attempt

[GrahamRA]

Hi there,

We have an issue with our WinCC OA touchscreen application. After a failed login attempt, it is nolonger possible to use the WinCC OA touchscreen keyboard to enter text into the login screen. Note that the application is two parts: a server application project which runs in the background, and the client application project which the user interacts with. This issue pertains to the client.

Hardware:
* SIMATIC IPC427E - Embedded IPC
* DisplayPort/USB Touchscreen

Software:
* Red Hat 8.4
* WinCC OA 3.17 P012

System Config:
* WinCC OA server project configured to start on system startup via systemd
* GNOME Display Manager GDM configured to load UI manager of WinCC OA client project without desktop environment (i.e. no KDE or Gnome, the UI manager is started within x11 directly)

Steps to reproduce:

1. At login prompt, select a user from the left-hand side.
2. Select the "Password" text field.
The WinCC OA touchscreen keyboard should appear
3. Type an incorrect password.
4. Press "OK" button to attempt login.
A dialog will appear which reads "Authentication error"
5. Press "OK" to dismiss the dialog.
6. Press the "Password" text field.
The WinCC OA touchscreen keyboard should appear again
7. Attempt to type a password

Observed Behaviour: The WinCC OA touchscreen keyboard appears, but the text cursor (blinking vertical line) does not appear within the password field, as such when pressing keys on the WinCC OA touchscreen keyboard, no characters are entered.

Expected Behaviour: It should be possible to attempt to login again.

Current workaround: Using the window manager Kwin (part of KDE) allows the keyboard to function as intended, however this is not a desirable solution to the problem as introducing a window manager, especially one which does compositing, introduces "features" such as animations and side-swiping which are against our requirements (the application should work in kiosk mode—the ability to access underlying parts of the system must be removed)

If anyone has any experience of touchscreen OA applications on Linux, please do share your knowledge!

Thanks,
Graham

[leoknipp]

I had a look at the description but I do not understand the first step:
1. At login prompt, select a user from the left-hand side

In the standard login panel there is no possibility to select a user. The username must be typed into the text field for the username.
Are you possibly using a modified login panel?
Does it work with the standard login panel?

If you need further assistance you can get in contact with your common WinCC OA support.

Best Regards
Leopold Knipp
Senior Support Specialist