Ignition Version : 8.1.24 Perspective I add a project Library. # messageBox def messageBox(title,message,sessionId=None,pageId=None): system.perspective.openPopup("messageBox",'Popup/messageBox', title=title,params = {'message':message}, showCloseIcon = True, resizable = True,modal=True,…

Do not provide session ID or page ID when opening a popup from within a page context. (Also, show us the real call to system.perspective.openPopup(), not just a call to a library function that is "understood" to do it for you.)

As @pturmel said in this thread [image] I want to open a popup when the value of the Perspective tag is changed Bind the tag to a custom property in the session or view where you want the popup. Add a change script to that property. Do not use a gateway tag change or tag value change for UI oper…

The most convenient place to do this is in a shared docked view for the entire project. The change event on one of its custom properties, bound to the tag, will have the context needed to unconditionally open a popup.

In Version 8.1.24: I try left menu add a custom property，bind to a tag; I add change script in it. But the popup also can't show . def valueChanged(self, previousValue, currentValue, origin, missedEvents): if previousValue is None: return # 只在False→True上升沿弹窗 …

I just did it this way on a project. I'm glad to hear that is considered a good way to do it :slight_smile:

[image] Steve_Laubach: a good way to do it I am biased toward UI tag bindings rather than messaging. Script in one place instead of two, and the "send" side is handled purely in java infrastructure.

Tag change open a popup in Perspective?

Ignition

JVDM June 3, 2026, 9:52am 2

As @pturmel said in this thread