Bug when using unit labels inside of array

[mbayc]

I believe there is a bug that is causing the labview front panel UI to no longer show  drop down lists, whether it be a ring, enum, or the the file-edit-view menus from the menu bar.

If you have a cluster that is part of an array and one of the cluster controls is set to display in "SI Notation" with a visible unit label, once you edit one of the unit label controls in the array of clusters then all the drop down lists become invisible. This happens while editing or running the VI. You can still guess and select a value, but it makes the entire front panel essentially unusable until the VI is closed and restarted. Even trying to save via "ctl+s" sometimes works sometimes hangs indefinitely once in the funky state.

If i disable the unit labels then this behavior seems to go away.

The attached LV2017-VI repeatably exhibits this behavior in a win 10 environment when the start or stop frequency fields in the cluster array are changed and set to display in "SI" notation with unit labels.

[aputman]

I understand that you are using WIN10 but FWIW, if I am understanding correctly your procedure for recreating this, I cannot duplicate this in WIN7 64bit using LabVIEW 2017 32bit.  I can change Start/Stop Freq controls to SI notation and enable/disable unit labels without causing any display issues of dropdown menus.  Could this be a video driver issue? 

[mbayc]

It could be something incompatible with the video driver and/or operating system. It's a bit odd, i was able to sort of fix the problem by deleting the numeric controls and adding them again to the cluster.

Though what i found out is that it was not the deletion and recreation that fixed it, but rather that the unit labels were back in their default position. When i moved the unit label to be centered on the control the problem reappeared until i undid the unit label move back to its default position then the problem doesn't come up...so far. It also doesn't seem to come up when moving/displaying/hiding in different combinations the caption or control's name label, it seems to just be related to the position of the unit label getting moved away from its default position.

I have to move on with my current project now that i've found a functional way to work with it, so don't have time to troubleshoot drivers and OS correlations at the moment. But i wanted to post it in case others find similar behavior in their configuration, maybe one day the specific cause can be found. I'm guessing as you are, that this may be related to a unique combination of display drivers, LV, and OS, that may be hard to recreate.

To that end, this is my CPU config.

Lenovo P1 laptop - up to date video driver 6.13.1.0

win 10 Pro version 1809, build 17763.475

LV 2017 SP1 (17.0.1f3)

[mbayc]

Update on some more findings. The disappearing drop down menus still happen even if i leave the unit label in the default position. I've found that it works best to simply not use the unit label. If i delete the units in the unit label, but leave the control display format in "SI notation" i still can get the (m, k, M) prefix to adapt automatically with the value. It just appears next to the number rather than the units label. If i put my units in a caption instead then i effectively get the same front panel information without the odd behavior.

So this is the work around I'm going to use.

[billko]

"Units" was a path NI took that was paved with good intentions; however, it must have been so difficult to implement that they gave up on it.  It is basically unfinished; lots of little bugs and peculiarities.  It is recommended to stay away from using them if you can.

[paul_cardinale]

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@billko wrote:

"Units" was a path NI took that was paved with good intentions; however, it must have been so difficult to implement that they gave up on it.  It is basically unfinished; lots of little bugs and peculiarities.  It is recommended to stay away from using them if you can.

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"Lots of ... bugs"?  I was only aware of 2: The square root bug (now fixed) and the numeric scale bug.

Please tell me about some others.

[Kyle97330]

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@paul_cardinale wrote: "Lots of ... bugs"?  I was only aware of 2: The square root bug (now fixed) and the numeric scale bug.

Please tell me about some others.

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Well, it's pretty weird that this block diagram produces a valid run arrow:

There's also this one that's a problem with the XML flattening and unflattening of units.