Bug: Hidden Iteration Terminal prevents resizing For and While Loops via Ctrl-Alt-drag

[maflAT]

Usually when resizing a for loop structure or while loop structure, the iteration terminal will move together with the lower left corner of the structure's border.

This is true when:

• terminal is visible and resizing the structure by grabbing the border,
• terminal is visible and resizing via Ctrl-drag or Ctrl-Alt-drag (and the start point for the drag operation is to the top right of the terminal),
• terminal is not visible and resizing by grabbing the border.

The same is NOT true when:

• terminal is not visible and resizing via Ctrl-drag or Ctrl-Alt-drag.

This means that reszing via Ctrl-Alt-drag is limited in range until the point when the border of the structure touches the (invisible) terminal.

Affected Version: LV 2021 SP1

Steps to reproduce:

1. Place for loop or while loop structure.
   
2. Hide iteration terminal.

3. Try to shrink the structure by Ctrl-Alt-clicking into the center of the structure and dragging towards the top-right.

   

Expected behaviour:

Structure shrinks unhindered as long as there are no other objects interfering with its border.

Actual behaviour:

The structures border is blocked by the invisible terminal and can't be resized by more than a few pixels.

Loop after failed resize attempt with iteration terminal re-enabled:

This same behaviour can be observed with for loops and while loops.

Event structures with a hidden event data node do not seem to be affected by this bug.

[thols]

I think you have auto-grow turned on. Turn it off and try again. It works for me as expected when auto-grow is not enabled.

[thols]

But I agree that it is not what I expect. If the "Iteration terminal" setting would have been on the "Visible Items" sub-menu, then I could maybe accept that the terminal simply is not visible but still there, but with the menu-selection as it is now, I would expect the iteration terminal to be removed entirely and thus not affect resizing regardless of auto-grow settings.

[billko]

That's a good one.  I guess I never noticed because the first thing I do is turn off auto-grow.

[maflAT]

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@thols wrote:

I think you have auto-grow turned on. Turn it off and try again. It works for me as expected when auto-grow is not enabled.

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The bug is even weirder than that.

I was about to disagree with your statement because I did not see any change in behaviour after disabling "Auto Grow" on an existing loop.

Turns out, I have the option "Place structures with Auto Grow enabled" checked in the options menu.

If i disable this option and place a new structure, the problem almost goes away.

Why almost?

Because after shrinking the loop with Ctrl-Alt-drag and subsequently re-enabling the iteration terminal, it does not show up at all:

Only after resizing the loop by a few more pixels via grabbing at the border it becomes visible again.

Again, this bug is not present when resiszing by grabbing the border of the loop.

[billko]

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@maflAT wrote:

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@thols wrote:

I think you have auto-grow turned on. Turn it off and try again. It works for me as expected when auto-grow is not enabled.

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The bug is even weirder than that.

I was about to disagree with your statement because I did not see any change in behaviour after disabling "Auto Grow" on an existing loop.

Turns out, I have the option "Place structures with Auto Grow enabled" checked in the options menu.

If i disable this option and place a new structure, the problem almost goes away.

Why almost?

Because after shrinking the loop with Ctrl-Alt-drag and subsequently re-enabling the iteration terminal, it does not show up at all:

Only after resizing the loop by a few more pixels via grabbing at the border it becomes visible again.

Again, this bug is not present when resiszing by grabbing the border of the loop.

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Thanks for the deep dive into the issue!

[thols]

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@maflAT wrote:

...

...

Because after shrinking the loop with Ctrl-Alt-drag and subsequently re-enabling the iteration terminal, it does not show up at all:

Only after resizing the loop by a few more pixels via grabbing at the border it becomes visible again.

Again, this bug is not present when resiszing by grabbing the border of the loop.

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You can make the i-terminal move beyond the loop border even when it is visible this way. In fact, now there is a way to get it back without enlarging the loop and searching for the terminal. Now you only need to disable and then enable the terminal and resize the loop by a pixel. It would be better it resizing was not needed and the terminal was placed within the loop bounds directly when enabling the terminal though.

But I have always wondered why it is allowed to move stuff outside of the loop borders but still be in the loop, hidden beneath the outer diagram. I guess that was one of the things that auto-grow tried to solve.

[thols]

I made an entry in the annual bug thread for this: https://forums.ni.com/t5/BreakPoint/Annual-bug-thread-for-2022/m-p/4201326/highlight/false#M32909

[wiebe@CARYA]

I've posted this before, but nobody seemed to care...

Note that showing or hiding the iteration terminal does not mark a VI as changed.

Steps to reproduce:

1) Using LV20 (haven't tried a more recent LV)

2) Create or open a VI with a loop.

3) Save it.

4) Show or hide the iteration terminal.

5) Notice there's no * to indicate that the VI has changed.

Save all won't save this VI. Next time the VI is loaded, the terminal is back to it's original state.

[Frozen]

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wiebe@CARYA wrote:

I've posted this before, but nobody seemed to care...

Note that showing or hiding the iteration terminal does not mark a VI as changed.

Steps to reproduce:

1) Using LV20 (haven't tried a more recent LV)

2) Create or open a VI with a loop.

3) Save it.

4) Show or hide the iteration terminal.

5) Notice there's no * to indicate that the VI has changed.

Save all won't save this VI. Next time the VI is loaded, the terminal is back to it's original state.

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That sounds like a different problem than the rest of this thread.