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Mistakes versus Intervening Variables: A Negative Proof of the Power of SDN

Recently I completed a custom program with a standard ALV that wasn’t resizing properly from low to high screen resolution or vice-versa. So after consulting the ABAP forum, I did what Thomas Jung suggested in a response he posted to someone back in 2004: make your custom container bigger than any possible screen size (e.g. 200, 240), turn on vert and hor resizing, and set your mins for both to something low – like 1 or 5. Didn’t work. Frustrated, I posted in the ABAP and ABAP OO Forums and got no responses except for one that Calgar was kind enough to post in ABAP OO that simply iterated what Thomas had said. What to do, what to do! Well, the very fact that I was getting no responses from the Forum folk should have made me realize sooner that the problem had to be at least partly on my side – that I was doing something that was causing the usual solution not to work. But, better late than never – I eventually realized that the SAP resizing algorithm wasn’t working properly because in my screen, I was calling a custom subscreen that was positioned above the container for the ALV. Apparently, this was causing the SAP resizing algorithm to hiccup, with the result that: 1) I was getting a window scroll-bar as well as an ALV scroll-bar; 2) the ALV was not scrolling properly after a find or findnext. So what can we all take away from this experience? Well, first, the story is a “negative proof” of the power of SDN. In particular, if you’re not getting any new insight from the Forums, it’s not because you’re being ignored – it’s because there IS no answer to the question you’ve asked other than the standard answer which you can already find with a search. Second – when the lack of any response in the Forums finally makes you realize the problem is certainly at least partly on your side, it’s important to remember that the problem may not be a “mistake” – it may simply be an “intervening variable” that has to be eliminated to see the “truth”, however improbable that truth may be. Third – the “improbable truth” is that there are minor oversights in SAP algorithms – even ones that have been around for a long time. PS to the real SAP gurus around here: In my PBO, I was calling the subscreen after firing the ALV display module. So I wonder if the SAP resizing algorithm would actually work correctly if I called the subscreen BEFORE firing the ALV display module ….. ???
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  • Hi,

    Thanks for a great blog. You are putting words to something that I frequently do. I hope it is ok that I add a couple of thoughts here …

    Sometimes I use SDN as a “pre-OSS”. If I missed something obvious, a quick answer is usually replied. If no answer from the forum, then it might be material for an OSS message.

    SDN can be a great place to discuss solutions. Many times there are more than one solution to a question and it can be good to reflect on pros and cons with other members. In other words, it is more than finding a solution, it is about finding an ELEGANT solution.

    Finally, I use SDN as an issue database. Even if I find the solution myself, then I always try to document carefully how I solved the issue.

    • Hi Bjorn-H – glad to know the thought resonated with you.  I also liked your comment about ELEGANT solutions as opposed to “just get it into production” solutions.  Too often, we have to do the latter in real life, so that’s another advantage of SDN – it’s a place to pretend you don’t have deadlines that always come too quickly because some high-margin low-risk functionals are off to their next assignment leaving you with an incomplete or misconceived spcec.