We had identified an issue in AP&P 26.4 where switching to other invoice tabs can randomly make those tabs unresponsive, after clicking the External link icon.
Issue Start: May 4, 2026
R&D has implemented and merged the fix in Basware release 26.4.3 and 26.5.
You can find the exact deployment date under Service Status > Extended Release Schedule in our Customer Service Portal.
In the release notes, the reference for this issue is the Support System Id BWPB0048792.
Impact Summary
After clicking the External link icon on the invoice view,
Then attempt to click on any of these tabs, they do not respond randomly.
This can only be reproduced on the latest 26.4 release.
Workaround
While waiting for the permanent fix, you can close the middle frame which was opened by the external link icon. Then all the other tabs respond normally afterwards.
Solution
This is an known issue reported to R&D with critical priority. The fix is done to 26.4.3 and 26.5 release.
You can find the exact deployment date under Service Status > Extended Release Schedule in our Customer Service Portal.
The Support System Id is BWPB0048792.
Further Support
If you would like to raise a case regarding this issue, please use this link: Support case
RCA
Service Incident Summary:
What Happened?
On April 27, 2026, we received a case from the customer that users who opened an invoice in a separate pinned window experienced unexpected behavior when switching between invoice tabs. In some cases, specific invoice sections stopped responding, preventing users from accessing or interacting with those tabs until the invoice view was refreshed or reopened. An issue was identified where, after popping out and pinning an invoice tab, navigating to other invoice tabs caused certain sections—such as Header Data, Discussions, and Attachments—to become unresponsive.
Root Cause Analysis:
Why and How did it Happen?
The issue was introduced as an unintended side effect of our user interface framework (Angular) upgrades performed as part of our modernization efforts.
Specifically, changes associated with the Angular upgrade altered the way tab state and component interactions were managed within the application. Under a specific scenario involving popped-out and pinned invoice tabs, the updated framework behavior caused certain tab components to lose responsiveness when users navigated between invoices.
The problem only manifested under the specific workflow of using pinned invoice tabs and switching between invoices.
Impact Analysis:
How are customers Impacted?
Approximately 60+ customer environments were affected by this issue.
Impacted users experienced the following behavior:
- Certain invoice tabs, including Header Data, Discussions, and Attachments, became unresponsive after an invoice tab had been popped out and pinned.
- Users were unable to access content within the affected tabs until the invoice session was refreshed or reopened.
There was:
- No service outage
- No downtime
- No data loss
- No rollback required
The impact was limited to the usability of the affected invoice tabs within the specific user workflow described above.
Timeline of Events:
Event Start: April 27, 2026
Event End: May 21, 2026
Corrective Measure
What are our Corrective Actions planned/completed to restore services for this incident?
The issue was corrected through a code change implemented at the Proton framework level, specifically within the tab.component implementation.
The fix restored the correct handling of tab state and interactions, ensuring that invoice tabs remain responsive when users work with popped-out and pinned invoice windows.
The correction was included in version 26.4.3.
Preventative Measures
What are our Preventative actions planned/completed to prevent the recurrence of this incident?
To reduce the likelihood of similar issues occurring in future releases, the following actions have been identified:
- Expanded Test Coverage
We are introducing additional test cases to validate scenarios involving popped-out and pinned invoice tabs and other advanced navigation workflows. - Automation of Regression Testing
We are introducing automated test cases to ensure that tab responsiveness is validated as part of future release cycles.
3. Framework Upgrade Validation
We will be performing enhanced regression testing during future framework and platform upgrades to identify UI interaction issues earlier in the development process.