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Annual bug thread for 2020


Continued from the Aug-Dec 2019 bug thread.


The monthly bug threads never got very long, so to avoid fragmentation, we are now doing one bug thread per year.


Happy New Hear everyone. May you all discover the last few remaining bugs with 2020 vision!


The rules remain the same:


  • Each post here should only contain a brief description of a bug, together with a link to the thread where it is being discussed.
  • One post/bug!
  • One bug/post!
  • No discussion of bugs. All discussions of a bug must take place in the original linked thread.

LabVIEW Champion. It all comes together in GCentral GCentral
What does "Engineering Redefined" mean??
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Message 1 of 26



Built-in Mouse Wheel support for Numeric/Ring/Enum Ctrl doesn't work when the ctrl is linked to connection pane.

LabVIEW 2014SP1 / 2019SP1

Windows 7 Pro


Work around: use Combo Box instead of Ring/Enum.


George Zou
Message 2 of 26

Creating a "VI for Override" when the parent class is a debugging-enabled PPL gives an error.


Bug number is 1047200 (replacing CAR).


Workaround is any of

a) Modify LabVIEW 2020\resource\Framework\Providers\LVClassLibrary\NewAccessors\VIRetooler\ to always error in the middle case structure

b) Don't use debugging-enabled PPLs

c) Manually override (don't use the scripting).

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Message 3 of 26

LabVIEW does not recognize modifications to override VIs after the initial save.


NI is aware of the issue, SLM seems to be working on it. CAR: 1057446

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Message 4 of 26

A few bugs? I have them plenty!


I still not sure which bugs should be posted here, but they're all either not-before-seen on a forum or not posted in any bug thread and not fixed for years.


Incorrect constant size and value after multiple Undo/Redo operations

CAR #1065457.

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Message 5 of 26

Combo Box doesn't allow single item with an empty value

Still no reply to SR.



  • Add more items into a Combo Box;
  • Use a " " (space), "." (dot) or another 1-char value as default item.
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Message 6 of 26

LabVIEW doesn't release memory for any 2+D / string arrays after VI stops executing

CAR #440207.


It was briefly mentioned on NI forums a couple of times as well, but nobody payed a close attention to the words. Here's basically a NI opinion.

The memory is reused, but it doesn't really help much.

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Message 7 of 26

Edit Format (Scan) String window doesn't escape "\" character (and it actually causes further issues...

CAR # is not yet received.


Output exact string operation doesn't check or escape backslash codes which causes format specifiers to be treated as part of a string and not added to the list.

Conversely, if you remove the second "\" character in Output exact string operation, the string will collapse with next format specifier.

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Message 8 of 26

Deadlock when using Set Time and Date dialog of a Time Stamp Control during profiling

CAR # is not yet received.


The only solution to this I've found is to kill LabVIEW in Task Manager.

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Message 9 of 26

Runtime panel size is being set incorrectly when window parts are hidden

Still no response to SR.


When Minimum Panel Size = runtime panel size, panel size is being set to Minimum Panel Size + size of hidden items (even though they are hidden) instead of values set in VI Properties > Window Run-Time Position > Panel Size.

The window can be shrunk to expected size manually at runtime.



  • Set Minimum Panel Size = runtime panel size - size of hidden items (-17 for Width, -63 for Height) or less;
  • Check Use Current Panel Size option at VI Properties > Window Run-Time Position.


This bug is about panel size at runtime being more than it should be.

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Message 10 of 26