NPE when closing MapTool after a macro is opened twice simultaneously for editing.

[Merudo]

Describe the bug
I've noticed an occasional NPE in the console when closing MapTool. When not using the console, I see a window popup for a split second while closing, exactly how it was for #700.

java.lang.NullPointerException: null
        at net.rptools.maptool.client.ui.MacroButtonDialog.updateOpenMacroList(MacroButtonDialog.java:299) ~[main/:?]
        at net.rptools.maptool.client.ui.MacroButtonDialog.access$100(MacroButtonDialog.java:84) ~[main/:?]
        at net.rptools.maptool.client.ui.MacroButtonDialog$1.windowClosed(MacroButtonDialog.java:149) ~[main/:?]
        at java.awt.AWTEventMulticaster.windowClosed(AWTEventMulticaster.java:368) ~[?:?]
        at java.awt.Window.processWindowEvent(Window.java:2081) ~[?:?]
        at javax.swing.JDialog.processWindowEvent(JDialog.java:686) ~[?:?]
        at java.awt.Window.processEvent(Window.java:2037) ~[?:?]
        at java.awt.Component.dispatchEventImpl(Component.java:4966) ~[?:?]
        at java.awt.Container.dispatchEventImpl(Container.java:2319) ~[?:?]
        at java.awt.Window.dispatchEventImpl(Window.java:2772) ~[?:?]
        at java.awt.Component.dispatchEvent(Component.java:4798) ~[?:?]
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772) ~[?:?]
        at java.awt.EventQueue.access$600(EventQueue.java:97) ~[?:?]
        at java.awt.EventQueue$4.run(EventQueue.java:721) ~[?:?]
        at java.awt.EventQueue$4.run(EventQueue.java:715) ~[?:?]
        at java.security.AccessController.doPrivileged(Native Method) ~[?:?]
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87) ~[?:?]
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97) ~[?:?]
        at java.awt.EventQueue$5.run(EventQueue.java:745) ~[?:?]
        at java.awt.EventQueue$5.run(EventQueue.java:743) ~[?:?]
        at java.security.AccessController.doPrivileged(Native Method) ~[?:?]
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87) ~[?:?]
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:742) ~[?:?]
        at net.rptools.maptool.client.swing.MapToolEventQueue.dispatchEvent(MapToolEventQueue.java:110) [main/:?]
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) [?:?]
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) [?:?]
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) [?:?]
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) [?:?]
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:?]
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:90) [?:?]

The problematic line appears to be

String id = button.getProperties().getMacroUUID();

To Reproduce
I'm unable to constantly reproduce this.

Expected behavior
No NPE when closing MapTool.

MapTool Info

• Version: 1.5.2 to 1.5.14, maybe earlier too
• Install: New

Desktop (please complete the following information):

• OS: Windows
• Version 10

[Phergus]

Is this only happening when a campaign is loaded and there are macros on a visible panel?

Perhaps the mouse pointer is hovering over a macro button as the panel is being disposed of and it is trying to get the macro ID to get a tooltip?

[Merudo]

Maybe? It only happens every now and then and usually by the time I see the error message I forgot what I just did.

[Merudo]

The steps in #1495 can be followed to replicate the bug.

[Merudo]

PR #1825 fixes this.

[Phergus]

Tested. No longer NPEs on exit after attempting to Edit a macro already open in an editor window.