CODESYS 2.3 can lose keyboard focus after an IntelliSense selection is accepted with Enter on Windows 10 Pro build 10.0.15063. The variable is inserted correctly, but the editor stops receiving keystrokes until focus is restored.
Identify the focus-loss symptom
Open an existing program, type until the IntelliSense popup appears, select a variable, and press Enter. This issue is present when CODESYS inserts the selected variable but its window immediately loses keyboard focus. The failure interrupts continuous entry, particularly when writing STL.
| Observation | Engineering interpretation |
|---|---|
| The selected variable is inserted | IntelliSense completes the selection before focus is lost. |
| Typing cannot continue | The CODESYS editor no longer owns keyboard focus. |
| A mouse click or Alt+Tab restores input | The editor remains open and can resume after focus is returned. |
| Other applications operate normally | The reported behavior is isolated to CODESYS 2.3 in the affected environment. |
Check the affected software environment
The documented case uses CODESYS 2.3.9.51 on Windows 10 Pro build 10.0.15063. The same CODESYS release had operated without this symptom on another Windows 10 Pro notebook, while additional reports associated the change with the Windows 10 Creators Update across multiple computers. This establishes a strong update correlation, but the available evidence does not identify the internal focus-handling defect.
Installing other CODESYS 2.3 versions did not resolve the documented case. A product representative stated that a correction had been approved for a subsequent release, but neither a release date nor a fixed version was identified. Do not treat an unspecified CODESYS release as corrected; verify the behavior directly after every update.
Work around and verify the problem
- After Enter inserts the IntelliSense selection, click the CODESYS window or use Alt+Tab to return focus.
- Continue typing and confirm that the editor receives keystrokes again.
- After installing any later CODESYS release, repeat the IntelliSense selection test. Accept the issue as resolved only if the variable is inserted and immediate typing continues without a mouse click or Alt+Tab.
The evidence provides no permanent configuration change. Until a verified corrected release is installed, restoring window focus is the documented operational workaround.
FAQ
Why does CODESYS 2.3 lose focus after IntelliSense?
The behavior was reported after the Windows 10 Creators Update, including Windows 10 Pro build 10.0.15063. The evidence supports an update-related correlation but does not establish the internal technical cause.
How do I restore keyboard focus in CODESYS 2.3?
Click the CODESYS window or use Alt+Tab. You can then continue editing after IntelliSense has inserted the selected variable.
Which CODESYS version fixes the IntelliSense focus problem?
No fixed version or release date is identified in the available evidence. Although a correction was approved for a later release, test IntelliSense focus retention after updating rather than assuming the issue is fixed.
