~= Speed Optimization =~
When the project is initially loaded, subside the individual tabs that the user opened in the past and load the data when the tab is actually opened (or selected into view if it was previously opened.)
When loading the html data for a screen or popup load only visible components as in the hidden ones below the page. Think of it as a buffer so the loaded components are only loaded when it is scrolled into view. Obviously not all screens are scrollable.
Multi Threading! Or some what. Since javascript has no asynchronous built in capabilities it may be difficult. Speed is the goal. Since your javascript code is quite intense this may be a massive game changer. I found a few great ways to do this for heavy code, check out This Page. Also this is an example http://sitepointstatic.com/examples/j... You may find some useful information and concepts there. I know this will make Appery fast. You could apply this when loading the initial project, components, and other information in bulk.
When a item in an element is changed make it so it does not automatically refresh the page. Maybe overlay a highlighted element over another that has been changed with the new value. That way the user can manually refresh the page. Maybe when they save it have a second button with "Save & Refresh" also have a checkbox for the settings with automatic refreshing and additionally checkboxes in each tab for maximum control. This could also be for events.
~= Making a Faster Workspace =~
Deletion of any element in a page or popup (tab) should be "marked for deletion" as in when clicking the red "X" button it should be removed BUT in some information panel say "Item Deleted (Undo?)" This is so a user can not only undo small actions but delete fast without risks. For example deleting 5 items will all show up in one panel. The user can individually undo each one or click "Undo all" also the user will also see a confirm button on each one looking like this "Item removed (Undo) ~ (Confirm)" This will make every deletion speedy.
Display a small icon next to an element with components in it. For example a bunch of items in a menu list. This can be painful to click the breadcrumb for the main component of the list just to change or delete it. So basically add an icon (maybe next to the red X button) add an up arrow or an action arrow to go to the parent component. This can help greatly
Add up and down arrows in menu list or collapsable lists. Add them on each item to move an item up or down to order the list. Maybe even a button to activate moving of individual items changing the cursor to that "+" sign indicating move. This will help speedy big list ordering.
Double clicking an already selected component should make the text field editable. Obviously it must be text. Maybe an icon selector if its an icon. or maybe An icon next to the red X button on an image should appear so you can easily change the image without selecting clicking and all of that time. Gone.
~= LIVE Editing! =~
Allow the use of live editing in the test window. Maybe a switch so if turned on, when something is updated, immediately change the items modified. This is to prevent that constant refresh for OCD users...
Optional mode that if the native app is in debug mode allow an auto refresh to be set maybe requiring a wifi connection for maximum workflow.
~= Want more? =~
Thanks for comments, if you want more please comment and let me know what to add or new sections. Lets make this list massive!