How can I delete a curve from a graph? thanks

[altenbach]

---

@smercurio_fc wrote:

I think this is incorrect behavior.

---

I agree, and I think it is probably collateral damage due to the fix of some much older bug where the custom plot legends got forgotten after closing and reopening a VI. 😞

[nickbike]

To further define a major problem with this, I've made some changes and added steps 22-25 to the instructions from smercurio_fc to recreate the issue with a waveform graph and cursors

---

smercurio_fc wrote:

1. With the code you provided, place a new chart graph on the VI. Do not change any properties of the chart.
2. Connect the chart to the output of the Merge Signals function.
3. Run the VI.
4. Open the properties on the plot legend, and you should see 10 plots.
5. Close the chart graph properties. Do NOT change anything.
6. Reconnect the chart graph to the output of the Select Signals VI.
7. Run the VI.
8. Open the properties on the plot legend, and you should see 2 plots. Expected behavior.
9. Close the chart graph properties. Do NOT change anything.
10. On the front panel, resize the plot's legend so that it shows up to, for example, Plot 5.
11. Open the properties on the plot legend. You should see 6 plots.
12. Close the chart graph properties. Do NOT change anything.
13. Run the VI.
14. Open the properties on the plot legend. You will still see 6 plots.
15. Close the chart graph properties. Do NOT change anything.
16. Resize the plot legend back to show only one plot.
17. Open the properties on the plot legend. You will still see 6 plots.
18. Close the chart graph properties. Do NOT change anything.
19. Run the VI.
20. Open the properties on the plot legend. You will still see 6 plots.
21. Close the graph properties. Do NOT change anything.
22. Right-click on the graph "visible items->cursor legend"
23. Rick-click on the cursor legend and select "create cursor->multi-plot"
24. Rick-click on the cursor just created in the cursor legend and select "Watch->All Plots"
25. Watch as all the extra plots now show up in your cursor legend (arghhhhhh!).

---

My user is going to be confused by all these extra plots especially since they are named. For example, load and graph one data file with 5 channels (speed, thermocouple 1, thermocouple 2, force 1, force 2). Now lets say only 3 channels were recorded in the next data file (speed, themocouple 1, thermocouple 2). If I used the same VI and graph to look at the data and the user puts a cursor on to look through the data, there will be the two extra channels of force 1 and force 2. This will lead the user to believe these two channels were recorded and for some reason they are blank.

[X.]

You probably want to rename these extra plots with an empty string name...

[nickbike]

---

@X. wrote:

You probably want to rename these extra plots with an empty string name...

---

Good point. That would eliminate some of the confusion, but the plots will still show up as blanks in the cursor legend. To get around this for now, I put a "create" and "delete" cursor button under the cursor lgend. When they user hits "create" it makes a cursor that is watching only the plots that were loaded when the VI was loaded instead of "All Plots".

[X.]

I'd say the cursor "feature" that you are describing is much more of an issue than the Property Dialog Window one described by smercurio_fc (which is problematic in Edit mode), but is most likely related.

I may remember having suffered from it in the past (obviously it is not a Chart issue, as there are no cursors available with Charts).

I'd file it as a bug. Where are the blue guys when you need them :-?

[YoMetric]

Hi, I am just wondering if this bug/issue was ever fixed?  I just came across this same issue where extra plot names are showing up in my cursor list when i have it set to "watch all".  I am currently running Labview 2011 SP1 and i'm just curious if this was fixed in a later version.

[X.]

Since there is no evidence that NI engineers understand what kind of aborrhent (and aberrant) UI this leads to, here is an example of a XY Graph where I cleared the Graph (wired an empty structure to it), cleared the plot names, shrunk the legend, hid the plots, etc and nevertheless still get a 100 "invisible and non-existing plots" accessible through the cursor menu.