Bad performance with Objects window when grouping, copying or deleting objects

In hindsight this is a duplicate of what would be merged from here: https://bugs.launchpad.net/inkscape/+bug/1431274

Steps to reproduce:

• open Inkscape
• open the "objects window"
• group multiple objects
• ungroup multiple objects
• copy multiple objects
• delete multiple objects

What happened?

• everything happens as expected but with a considerable lag and CPU spike

What should have happened?

• simple tasks as described above should happen instantly, even when the "objects window" is open

Inkscape Version and Operating System:

• Inkscape Version: 1.0alpha (1:0.92.0+devel+201904180550+646ed5b)
• Operating System: Ubuntu
• Operating System version: 19.04

copy-paste-group

I started inkcsape in terminal this is what i get from there

** (inkscape:2963): WARNING **: 12:18:31.413: Failed to find resource file 'inkex.py'. Looked in:
	/home/mray/.config/inkscape/extensions/inkex.py
	/usr/share/inkscape/extensions/inkex.py

** (inkscape:2963): WARNING **: 12:18:31.413: Failed to find resource file 'inkex.py'. Looked in:
	/home/mray/.config/inkscape/extensions/inkex.py
	/usr/share/inkscape/extensions/inkex.py

** (inkscape:2963): WARNING **: 12:18:31.413: Failed to find resource file 'inkex.py'. Looked in:
	/home/mray/.config/inkscape/extensions/inkex.py
	/usr/share/inkscape/extensions/inkex.py
Pango version: 1.42.3

** (inkscape:2963): WARNING **: 12:18:31.485: Fonts dir '/home/mray/.config/inkscape/fonts' does not exist and will be ignored.
Unable to find: org.inkscape.typography.newglyphlayer

** (inkscape:2963): WARNING **: 12:18:31.777: Unknown verb name: org.inkscape.typography.newglyphlayer
Unable to find: org.inkscape.typography.newglyphlayer

** (inkscape:2963): WARNING **: 12:18:31.777: Unknown verb name: org.inkscape.typography.newglyphlayer
Unable to find: org.inkscape.typography.nextglyphlayer

** (inkscape:2963): WARNING **: 12:18:31.777: Unknown verb name: org.inkscape.typography.nextglyphlayer
Unable to find: org.inkscape.typography.nextglyphlayer

** (inkscape:2963): WARNING **: 12:18:31.777: Unknown verb name: org.inkscape.typography.nextglyphlayer
build_menu: xml is nullptr
Unable to find: org.inkscape.help.manual
build_menu: no verb with id: org.inkscape.help.manual
Unable to find: org.inkscape.help.keys
build_menu: no verb with id: org.inkscape.help.keys
Unable to find: org.inkscape.help.askaquestion
build_menu: no verb with id: org.inkscape.help.askaquestion
Unable to find: org.inkscape.help.commandline
build_menu: no verb with id: org.inkscape.help.commandline
Unable to find: org.inkscape.help.faq
build_menu: no verb with id: org.inkscape.help.faq
Unable to find: org.inkscape.help.relnotes
build_menu: no verb with id: org.inkscape.help.relnotes
Unable to find: org.inkscape.help.reportabug
build_menu: no verb with id: org.inkscape.help.reportabug
Unable to find: org.inkscape.help.svgspec
build_menu: no verb with id: org.inkscape.help.svgspec
Warning: Font face with same CSS values already added: Ubuntu Medium Italic (Medium Italic, Medium Italic)
Warning: Font face with same CSS values already added: Ubuntu Medium (Medium, Medium)

(inkscape:2963): Gtk-WARNING **: 12:19:06.371: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node notebook owner GdlSwitcher)

(inkscape:2963): Gtk-WARNING **: 12:19:06.371: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node stack owner GdlSwitcher)

(inkscape:2963): Gtk-CRITICAL **: 12:19:06.426: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:19:06.531: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:19:16.310: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:19:23.496: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:19:28.875: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:19:30.604: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:23.002: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:24.240: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:34.927: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:35.900: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:42.970: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:20:53.206: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:21:58.066: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:21:58.766: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher
SPDocument::doUnref(): invalid ref count! -1

(inkscape:2963): Gtk-CRITICAL **: 12:22:05.296: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.081: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.104: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.124: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.464: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.484: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:11.505: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher

(inkscape:2963): Gtk-CRITICAL **: 12:22:16.951: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GdlSwitcher
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1
SPDocument::doUnref(): invalid ref count! -1