Hello again,   I did a bit more digging and still do not have a solution, but narrowed down the issue. It appears that the dropdown list resets itself when the onChange function affects something outside the palette, like triggering an alert or changing something in After Effects. However, it works correctly when the onChange function affects the palette itself, like checking a box.   At the bottom of the post, I pasted the code for an updated script that demonstrates the issue. It has 3 dropdown lists: One does nothing. The second triggers an alert, which behaves incorrectly and resets itself when it shouldn’t. The third checks/unchecks boxes and behaves correctly.   Hopefully someone from Adobe can replicate the issue and confirm it's a bug.   Thank you.   var panelGlobal = this; // DIALOG // ====== var dialog = (panelGlobal instanceof Panel) ? panelGlobal : new Window("palette"); if ( !(panelGlobal instanceof Panel) ) dialog.text = "Dropdown Test"; dialog.orientation = "row"; dialog.alignChildren = ["center","top"]; dialog.spacing = 10; dialog.margins = 16; // PANEL_DONOTHING // =============== var panel_DoNothing = dialog.add("panel", undefined, undefined, {name: "panel_DoNothing"}); panel_DoNothing.text = "Do Nothing"; panel_DoNothing.orientation = "column"; panel_DoNothing.alignChildren = ["left","top"]; panel_DoNothing.spacing = 10; panel_DoNothing.margins = 10; var dd_DoNothing_array = ["Item 1","Item 2","Item 3"]; var dd_DoNothing = panel_DoNothing.add("dropdownlist", undefined, undefined, {name: "dd_DoNothing", items: dd_DoNothing_array}); dd_DoNothing.selection = 0; // PANEL_ALERT // =========== var panel_Alert = dialog.add("panel", undefined, undefined, {name: "panel_Alert"}); panel_Alert.text = "Alert"; panel_Alert.orientation = "column"; panel_Alert.alignChildren = ["left","top"]; panel_Alert.spacing = 10; panel_Alert.margins = 10; var dd_Alert_array = ["Item 1","Item 2","Item 3"]; var dd_Alert = panel_Alert.add("dropdownlist", undefined, undefined, {name: "dd_Alert", items: dd_Alert_array}); dd_Alert.selection = 0; // PANEL_CHECKBOX // ============== var panel_Checkbox = dialog.add("panel", undefined, undefined, {name: "panel_Checkbox"}); panel_Checkbox.text = "Check boxes"; panel_Checkbox.orientation = "column"; panel_Checkbox.alignChildren = ["center","top"]; panel_Checkbox.spacing = 10; panel_Checkbox.margins = 10; // GRP_CHECKBOXES // ============== var grp_Checkboxes = panel_Checkbox.add("group", undefined, {name: "grp_Checkboxes"}); grp_Checkboxes.orientation = "row"; grp_Checkboxes.alignChildren = ["left","center"]; grp_Checkboxes.spacing = 17; grp_Checkboxes.margins = 0; var checkbox1 = grp_Checkboxes.add("checkbox", undefined, undefined, {name: "checkbox1"}); checkbox1.text = "1"; var checkbox2 = grp_Checkboxes.add("checkbox", undefined, undefined, {name: "checkbox2"}); checkbox2.text = "2"; var checkbox3 = grp_Checkboxes.add("checkbox", undefined, undefined, {name: "checkbox3"}); checkbox3.text = "3"; var dd_Checkboxes_array = ["Box 1","Box 2","Box 3"]; var dd_Checkboxes = panel_Checkbox.add("dropdownlist", undefined, undefined, {name: "dd_Checkboxes", items: dd_Checkboxes_array}); dd_Checkboxes.selection = 0; dialog.layout.layout(true); dialog.layout.resize(); dialog.onResizing = dialog.onResize = function () { this.layout.resize(); } if ( dialog instanceof Window ) dialog.show(); //Test dropdown list by showing alert dd_Alert.onChange = function () { alert("Dropdown 2 - TEST!!\nDoes the list clear after clicking OK?"); } //Test dropdown list by checking/unchecking boxes in palette dd_Checkboxes.onChange = function () { var listNum = dd_Checkboxes.selection.index; switch(listNum){ case 0: (checkbox1.value) ? checkbox1.value = false : checkbox1.value = true; break; case 1: (checkbox2.value) ? checkbox2.value = false : checkbox2.value = true; break; case 2: (checkbox3.value) ? checkbox3.value = false : checkbox3.value = true; break; } }   ... View more

Hello All, I just wanted to provide a status update. This morning, I upgraded to the newest version of After Effects CC, Version 15.1.0 (Build 166), which I believe was released on April 8th. I am happy to report that, so far, it's looking like Adobe has resolved the issue. I haven't fully run it through it's paces yet, but I have tested it out on a few expression heavy projects. I was successfully able to render and then make changes within the project, which were accurately updated in the comp view...without having to use the work around of closing and then reopening the project after the render completed. Does anyone else that has been experiencing the issue have the time/resources to upgrade and to run a few tests? It would be great to have someone else confirm these results. Thanks in advance and hopefully this bug has finally been fixed! -Mike ... View more

Nothing with an expression seems to update in the comp view. When I started to notice this issue, I experimented with trying to create some basic projects to see if I could replicate the issue. Here's what I found: When there are only a handful of expressions, maybe 10-20 or so, the issue still occurs. But it seems like AE can snap itself out of whatever the cause of the issue is after changing the value of whatever is driving the expression, such as text or an expression control. After changing those values a few times, the comp window will start to update. It was never consistent, and there seemed to be no set number of times the value needed to be changed to get things working again. When the project is expression heavy...Once I render the expressions no longer work properly and the comp window does not update. I could never figure out what the tipping point is...how many expressions does it take, or what type of functions the expressions are performing, that cause AE to not recover properly after rendering. All of these projects worked fine in CC 2014. We only started having these issues once we updated to CC 2017 and 2018. Thanks again for all of your help! -Mike ... View more

I just tried it in the latest version of CC 2018, version 15.0.1 (Build 73). Unfortunately it's still not working, the expressions do not update after rendering. Is that the most current version? I did not see any updates in the CC application. Thanks for you help! -Mike ... View more

FWIW, I've been having the same issue since updating to CC2017....After rendering, expressions no longer update the comp preview, but they do update in the timeline. I posted the thread that pegeseus referred to: Expressions stop working after rendering CC2017​. I just wanted to add my voice as someone else that is experiencing this bug. I don't know what's going on in the background, but I do agree that it seems like AE is having issues with the cache. I can confirm that purging the cache does nothing. Although saving, closing and then reopening the project seams to remedy the problem...But it's a work around, not a solution. I create a lot of toolkits for people that are not that savvy with AE, so it's especially frustrating for them as they don't really understand what's going on. Hopefully some from Adobe can figure out a solution soon. Thanks for everyones input and suggestions! -Mike ... View more

Thank you for sharing the link! ... View more