Keyboard could not be grabbed

I am running Shutter (my favourite by the way) on Ubuntu machines for quite some time, but recently I changed my window manager to i3wm, but I am having problems there.
Shutter only works for Selection screenshot, all others fail with the message:

"Error while taking the screenshot. Keyboard could not be grabbed."

(image attached)

I ran it in debug mode, and found lots of issues I am not quite sure about which one could be related to this, so I decided to open this ticket.

The debugging output was (ran it and tried to take 3 desktop screenshots):

---

$ shutter -d
WARNING: gnome-web-photo is missing --> screenshots of websites will be disabled!

WARNING: Net::DBus::GLib is missing --> Ubuntu One support will be disabled!

WARNING: Image::ExifTool is missing --> Writing Exif information will be disabled!

INFO: gathering system information...

Linux mac17 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

Ubuntu 12.04 LTS \n \l

Glib 1.241
Gtk2 1.223

Glib built for 2.30.1, running with 2.32.3
Gtk2 built for 2.24.6, running with 2.24.10

3D reflection - /usr/share/shutter/resources/system/plugins/perl/sp3dreflection/sp3dreflection
3D rotate - /usr/share/shutter/resources/system/plugins/perl/sp3drotate/sp3drotate
Barrel Distortion - /usr/share/shutter/resources/system/plugins/perl/spbardistortion/spbardistortion
Bordereffects - /usr/share/shutter/resources/system/plugins/perl/spbordereffects/spbordereffects
Negate - /usr/share/shutter/resources/system/plugins/perl/spnegate/spnegate
Polaroid - /usr/share/shutter/resources/system/plugins/perl/sppolaroid/sppolaroid
Resize - /usr/share/shutter/resources/system/plugins/perl/spresize/spresize
Sepia - /usr/share/shutter/resources/system/plugins/perl/spsepia/spsepia
Hard Shadow - /usr/share/shutter/resources/system/plugins/perl/spshadow/spshadow
Watermark - /usr/share/shutter/resources/system/plugins/perl/spwatermark/spwatermark
Shutter Branding - /usr/share/shutter/resources/system/plugins/shell/spaddlogo/spaddlogo
Grayscale - /usr/share/shutter/resources/system/plugins/shell/spgrayscale/spgrayscale
Jigsaw Piece 1 - /usr/share/shutter/resources/system/plugins/shell/spjigsaw1/spjigsaw1
Jigsaw Piece 2 - /usr/share/shutter/resources/system/plugins/shell/spjigsaw2/spjigsaw2
Offset - /usr/share/shutter/resources/system/plugins/shell/spoffset/spoffset
Raise Border - /usr/share/shutter/resources/system/plugins/shell/spraise/spraise
Soft Edges - /usr/share/shutter/resources/system/plugins/shell/spsoftedges/spsoftedges
Sunk Border - /usr/share/shutter/resources/system/plugins/shell/spsunk/spsunk
Torned Paper - /usr/share/shutter/resources/system/plugins/shell/sptornedpaper/sptornedpaper
Autocrop - /usr/share/shutter/resources/system/plugins/shell/sptrim/sptrim

INFO: new upload-plugin information detected - /usr/share/shutter/resources/system/upload_plugins/upload/Dropbox
Can't locate Net/Dropbox/API.pm in @INC (@INC contains: /usr/share/shutter/resources/modules /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/shutter/resources/system/upload_plugins/upload/Dropbox.pm line 73.
BEGIN failed--compilation aborted at /usr/share/shutter/resources/system/upload_plugins/upload/Dropbox.pm line 73.

ERROR: upload-plugin exists but does not work properly - /usr/share/shutter/resources/system/upload_plugins/upload/Dropbox
Current window manager: i3

type_changed was emitted by widget Gtk2::ComboBox=HASH(0x2791990)

qvalue_changed was emitted by widget Gtk2::HScale=HASH(0x4f5e0a0)

progname_toggled was emitted by widget Gtk2::CheckButton=HASH(0x277b208)

im_colors_changed was emitted by widget Gtk2::ComboBox=HASH(0x277b220)

im_colors_toggled was emitted by widget Gtk2::CheckButton=HASH(0x4f524e8)

thumbnail_changed was emitted by widget Gtk2::HScale=HASH(0x4f52428)

thumbnail_toggled was emitted by widget Gtk2::CheckButton=HASH(0x4f523e0)

bordereffect_toggled was emitted by widget Gtk2::CheckButton=HASH(0x4f52368)

bordereffect_changed was emitted by widget Gtk2::SpinButton=HASH(0x4f52320)

menu_delay_changed was emitted by widget Gtk2::SpinButton=HASH(0x2765eb0)

keybinding_sel_toggled was emitted by widget Gtk2::CheckButton=HASH(0x4f51768)

hide_time_changed was emitted by widget Gtk2::SpinButton=HASH(0x4f4c8f8)

ns_changed was emitted by widget Gtk2::ComboBox=HASH(0x4f4c8c8)
Use of uninitialized value in numeric le (<=) at /usr/bin/shutter line 9020.

full was emitted by widget Gtk2::MenuToolButton=HASH(0x27f1c90)
3 Ns used in wild-card
Searching for files with pattern: (?^u:20120707_(\d\d\d)\.jpeg)
Searching for files with pattern: (?^u:20120707_(\d\d\d)\.jpeg)
Comparing 20120702_001.jpeg
Comparing Screenshot from 2012-07-07 12:10:33.png
Comparing Screenshot from 2012-06-28 23:10:11.png
Comparing 20120629_001.jpeg
Comparing 20120706_001.jpeg
Comparing 20120616_90f4.jpeg
Comparing 20120629_002.jpeg
Comparing 20120707_001.jpeg
001 is currently greatest value...
Comparing 20120628_002.jpeg

full was emitted by widget Gtk2::MenuToolButton=HASH(0x27f1c90)
3 Ns used in wild-card
Searching for files with pattern: (?^u:20120707_(\d\d\d)\.jpeg)
Searching for files with pattern: (?^u:20120707_(\d\d\d)\.jpeg)
Comparing 20120702_001.jpeg
Comparing Screenshot from 2012-07-07 12:10:33.png
Comparing Screenshot from 2012-06-28 23:10:11.png
Comparing 20120629_001.jpeg
Comparing 20120706_001.jpeg
Comparing 20120616_90f4.jpeg
Comparing 20120629_002.jpeg
Comparing 20120707_001.jpeg
001 is currently greatest value...
Comparing 20120628_002.jpeg

Gtk2::Gdk::Event=SCALAR(0x4f40c78) was emitted by widget Gtk2::Window=HASH(0x477e770)

3, 68754845 was emitted by widget Gtk2::StatusIcon=HASH(0x4c32b88)

quit was emitted by widget Gtk2::ImageMenuItem=HASH(0x4a1a660)
WARNING: DBus connection to org.freedesktop.compiz failed --> setting keyboard shortcuts may not work when using compiz

org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.compiz was not provided by any .service files

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Any ideas of what could be the problem?

Thanks,