Photon Dan and JoeLabVIEW --
Thanks for the responses. At your suggestion, I made a simple event queue loop with sliders like the one that prompted my request for help. And, like you, there was no spurious second instance of the event. My original program is written to effect serial comms with a DUT and GPIB comms with an array of test equipment. A slider value change by clicking in the slider proper launches two identical sets of serial and GPIB writes. But a discrete numerical entry in the digital display tied to the slider launches only one.
The test program that I wrote to confirm your observations was not run on the same PC as the one exhibiting the aberrant behavior. Maybe there is a windows or mouse hardware or mouse mechanical action or antivirus or other background TSR issue. I will try my test program on that PC as soon as I can. Then I will add a new slider to see if it does the same thing as the originals. There are three in the GUI. I made the first, then copied it, so if the first was somehow corrupted, the others would be, as well. (The code would need a few mods for you to try to run it without the GPIB card and the externally connected equipment, and the excised code may prove to be part of the trouble.)
Thanks again for your generous responses. I will post a resolution if I find one.
