1... Don't use two separate property nodes for setting ACT PLOT and PLOT VISIBLE. If you do that, you don't know which will execute first - they're unrelated. Use a single property node (stretch it to include two properties). The top property should be ACTPLOT, the 2nd one should be PLOT VISIBLE. That way, it's guaranteed to execute in the order you need. 2... You are reading the checkbox cluster ONCE at the start of the program, and using that same value every time. You want to read the cluster WHEN THE CHANGE EVENT occurs, i.e., within the EVENT case. You can read the terminal, or read the NEW VALUE property of the event, either way is OK. But you have to read the new value, not the old one. 3... You are also reading your knobs ONCE at the start of the program, and re-plotting the same value every time you plot. You need to figure out when you should plot them, THEN read them and drive the chart. 4... If you set the timeout to, say, 100 mSec, and in the TIMEOUT event, read the knobs, and drive the chart, then you will have a live chart that updates roughly every 100 mSec. Implement #1 and #2, and you can turn the plots on and off. I say "Roughly" because of the way the timeout works - if you wait 99 mSec and then click a checkbox, the checkbox handler wins, and the 100mSec timer STARTS OVER when you get to the next iteration. If you want the chart to update exactly every 100 mSec then use a separate WHILE loop, with a WAIT TIL NEXT MSEC MULTIPLE. Do the wait, read the knobs, drive the chart, and repeat. A separate loop will not be disturbed by events in the UI loop.Message Edited by CoastalMaineBird on 08-15-2008 09:18 AMMessage Edited by CoastalMaineBird on 08-15-2008 09:21 AM