MATE-menu editor crashing when adding menu items or categories

[pastlife]

First time poster, I'm not an experienced Linux user. (2+ years full time on Linux so far) Sorry about formatting.

Whenever I right click and edit the mate-menu, I am unable to add new items to the list in the main menu editor, and sometimes cannot create new categories.

I click create launcher and then add the icon, name, command and select OK, but nothing is added to the menu. Also sometimes the entire menu editor windows crash (including the item pop-up editor), or just the main menu editor crashes. This happens for items as well as menu categories.

Here is a snip from `/var/log/syslog` which shows some errors during those times.

```
Nov 3 17:57:13 pleiades org.mate.panel.applet.MateMenuAppletFactory[28083]: X protocol error:
Nov 3 17:57:13 pleiades org.mate.panel.applet.MateMenuAppletFactory[28083]: <class 'Xlib.error.BadAccess'>: code = 10, resource_id = 1729, sequence_number = 479, major_opcode = 28, minor_opcode = 0
Nov 3 17:57:13 pleiades org.mate.panel.applet.MateMenuAppletFactory[28083]: X protocol error:
Nov 3 17:57:13 pleiades org.mate.panel.applet.MateMenuAppletFactory[28083]: <class 'Xlib.error.BadAccess'>: code = 10, resource_id = 1729, sequence_number = 490, major_opcode = 28, minor_opcode = 0
Nov 3 17:57:14 pleiades wnck-applet[2437]: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)
Nov 3 17:57:14 pleiades wnck-applet[2437]: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)

Nov 3 17:58:00 pleiades wnck-applet[2437]: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)
Nov 3 17:58:00 pleiades wnck-applet[2437]: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)

Nov 3 18:24:25 pleiades org.mate.panel.applet.MateMenuAppletFactory[50786]: X protocol error:
Nov 3 18:24:25 pleiades org.mate.panel.applet.MateMenuAppletFactory[50786]: <class 'Xlib.error.BadAccess'>: code = 10, resource_id = 1729, sequence_number = 178, major_opcode = 28, minor_opcode = 0
Nov 3 18:24:25 pleiades org.mate.panel.applet.MateMenuAppletFactory[50786]: X protocol error:

Nov 3 18:24:25 pleiades org.mate.panel.applet.MateMenuAppletFactory[50786]: <class 'Xlib.error.BadAccess'>: code = 10, resource_id = 1729, sequence_number = 189, major_opcode = 28, minor_opcode = 0
Nov 3 18:24:27 pleiades wnck-applet[2437]: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)
Nov 3 18:24:41 pleiades kernel: [111597.601741] mozo[50968]: segfault at 0 ip 00007f8b76f5d747 sp 00007ffe900c2168 error 6 in libmate-menu.so.2.4.9[7f8b76f5a000+d000]
Nov 3 18:24:41 pleiades kernel: [111597.601776] Code: da fe ff ff e8 5a d9 ff ff 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 f0 83 07 01 c3 0f 1f 40 00 f3 0f 1e fa 48 89 f8 <f0> 83 07 01 c3 0f 1f 40 00 f3 0f 1e fa f0 83 2f 01 74 06 c3 0f 1f
Nov 3 18:24:54 pleiades wnck-applet[2437]: message repeated 2 times: [ Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner WnckButton)]
```

This might be a bug related to another issue, which is that the panels and desktop icons are crashing completely, leaving me with an empty desktop, whenever I attempt to change the theme to a stock one. I have to reboot to get my panels back.

The other thing is that no matter what I do, I cannot set Super-L to actually open the menu. No action when I strike it, or sometimes it highlights the menu icon, but still wont open if I strike the Super-L or hit Enter while the mate-menu icon is highlighted. I can set it to other keys, just not Super-L. It's not the keyboard I promise.

Here is my original post about it at the Ubuntu-Mate community:

https://ubuntu-mate.community/t/mate-menu-errors-and-crashing-while-editing-items-and-categories/26039