I've seen clients suffering with an UI like this for decades. One of them had our help migrating to Salesforce last year.
The last one I've seen was an app developed in the early 2000s, I think in C# or maybe even Visual Basic, who knows?
The users wanted to expand the tiny window designed for those ancient 14-inch CRT monitors but the app wouldn't allow them to resize and use the full area of modern LCDs. 😫
One major challenge is having to have the old and new system side by side with integrations moving data between them and the users having to perform tasks in both systems ("swivel chair" process) ...
... until the client finally gets the budget to complete the migration. 😓
