hi
I'm having trouble loading the image you linked, can you upload it here as an attachment? (if it's too big use jpg instead of png)
also can you describe a little better what you did, I'm not sure what to do for reproduce your bug.

nevermind, I sort of figured it out, and I can confirm in branch and trunk.

adding a button into krita's toolbar will increase the right dockers' width, this new size appears fixed and I can't return it like it was before

1. right click in krita's toolbar and select configure toolbar
2. add any button, or a separator
3. apply
- the left dockers increase its size a bit
4. remove the item you added into the toolbar and press apply again
- the dockers increase its size again
5. you can repeat until krita's window is wider than the screen

I can't find a way to return it to normal, only after restarting krita I can fix it by resizing with the mouse

I cannot really reproduce, but that's mainly because I got a crash when I tried it:

Application: Krita (krita), signal: Segmentation fault
[KCrash Handler]
#6  QDomNamedNodeMapPrivate::clone (this=0x8628540, p=0x9989650) at dom/qdom.cpp:3069
#7  0xb598f6ab in QDomElementPrivate (this=0x9989650, n=0x86a81d8, deep=<value optimized out>) at dom/qdom.cpp:4424
#8  0xb598fa34 in QDomElementPrivate::cloneNode (this=0x86a81d8, deep=<value optimized out>) at dom/qdom.cpp:4437
#9  0xb598a2a0 in QDomNodePrivate (this=0x9988fd8, n=0x86b52a8, deep=true) at dom/qdom.cpp:1485
#10 0xb598f694 in QDomElementPrivate (this=0x9988fd8, n=0x86b52a8, deep=64) at dom/qdom.cpp:4422
#11 0xb598fa34 in QDomElementPrivate::cloneNode (this=0x86b52a8, deep=<value optimized out>) at dom/qdom.cpp:4437
#12 0xb598a2a0 in QDomNodePrivate (this=0x9988f90, n=0x9162238, deep=true) at dom/qdom.cpp:1485
#13 0xb598f694 in QDomElementPrivate (this=0x9988f90, n=0x9162238, deep=64) at dom/qdom.cpp:4422
#14 0xb598fa34 in QDomElementPrivate::cloneNode (this=0x9162238, deep=<value optimized out>) at dom/qdom.cpp:4437
#15 0xb598a2a0 in QDomNodePrivate (this=0x9215538, n=0x8e5d620, deep=true) at dom/qdom.cpp:1485
#16 0xb598f694 in QDomElementPrivate (this=0x9215538, n=0x8e5d620, deep=64) at dom/qdom.cpp:4422
#17 0xb598fa34 in QDomElementPrivate::cloneNode (this=0x8e5d620, deep=<value optimized out>) at dom/qdom.cpp:4437
#18 0xb598a2a0 in QDomNodePrivate (this=0x9988f40, n=0x8edd950, deep=true) at dom/qdom.cpp:1485
#19 0xb598f384 in QDomDocumentPrivate (this=0x9988f40, n=0x8edd950, deep=64) at dom/qdom.cpp:6185
#20 0xb598f434 in QDomDocumentPrivate::cloneNode (this=0x8edd950, deep=<value optimized out>) at dom/qdom.cpp:6260
#21 0xb5987386 in QDomNode::cloneNode (this=0xbf8b0d4c, deep=28) at dom/qdom.cpp:2358
#22 0xb6ab3f38 in KXMLGUIFactory::removeClient (this=0x86785c8, client=0x8293588) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/xmlgui/kxmlguifactory.cpp:425
#23 0xb68ee5ef in KDEPrivate::KEditToolBarWidget::rebuildKXMLGUIClients (this=0x8731938) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/dialogs/kedittoolbar.cpp:791
#24 0xb68efef9 in KDEPrivate::KEditToolBarWidget::save (this=0x8731938) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/dialogs/kedittoolbar.cpp:769
#25 0xb68f004b in KEditToolBarPrivate::_k_slotOk (this=0x9557668) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/dialogs/kedittoolbar.cpp:599
#26 0xb68f2913 in KEditToolBar::qt_metacall (this=0xbf8b31c8, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbf8b0f68) at /usr/src/debug/kdelibs-4.2.88svn973768/build/kdeui/kedittoolbar.moc:78
#27 0xb7e87dc8 in QMetaObject::activate (sender=0xbf8b31c8, from_signal_index=45, to_signal_index=45, argv=0x0) at kernel/qobject.cpp:3120
#28 0xb7e89552 in QMetaObject::activate (sender=0xbf8b31c8, m=0xb6b71084, local_signal_index=9, argv=0x0) at kernel/qobject.cpp:3194
#29 0xb68e3cd7 in KDialog::okClicked (this=0xbf8b31c8) at /usr/src/debug/kdelibs-4.2.88svn973768/build/kdeui/kdialog.moc:252
#30 0xb68e6518 in KDialog::slotButtonClicked (this=0xbf8b31c8, button=4) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/dialogs/kdialog.cpp:854
#31 0xb68e872c in KDialog::qt_metacall (this=0xbf8b31c8, _c=QMetaObject::InvokeMetaMethod, _id=33, _a=0xbf8b112c) at /usr/src/debug/kdelibs-4.2.88svn973768/build/kdeui/kdialog.moc:184
#32 0xb68f288a in KEditToolBar::qt_metacall (this=0xbf8b31c8, _c=QMetaObject::InvokeMetaMethod, _id=69, _a=0xbf8b112c) at /usr/src/debug/kdelibs-4.2.88svn973768/build/kdeui/kedittoolbar.moc:71
#33 0xb7e87dc8 in QMetaObject::activate (sender=0x9239ad8, from_signal_index=4, to_signal_index=4, argv=0xbf8b112c) at kernel/qobject.cpp:3120
#34 0xb7e89552 in QMetaObject::activate (sender=0x9239ad8, m=0xb7f67878, local_signal_index=0, argv=0xbf8b112c) at kernel/qobject.cpp:3194
#35 0xb7e8ad03 in QSignalMapper::mapped (this=0x9239ad8, _t1=4) at .moc/release-shared/moc_qsignalmapper.cpp:95
#36 0xb7e8b58d in QSignalMapper::map (this=0x9239ad8, sender=0x85f8078) at kernel/qsignalmapper.cpp:266
#37 0xb7e8b77e in QSignalMapper::map (this=0x9239ad8) at kernel/qsignalmapper.cpp:257
#38 0xb7e8c0bb in QSignalMapper::qt_metacall (this=0x9239ad8, _c=QMetaObject::InvokeMetaMethod, _id=4, _a=0xbf8b12ac) at .moc/release-shared/moc_qsignalmapper.cpp:81
#39 0xb7e87dc8 in QMetaObject::activate (sender=0x85f8078, from_signal_index=29, to_signal_index=30, argv=0xbf8b12ac) at kernel/qobject.cpp:3120
#40 0xb7e88200 in QMetaObject::activate (sender=0x85f8078, m=0xb636d244, from_local_signal_index=2, to_local_signal_index=3, argv=0xbf8b12ac) at kernel/qobject.cpp:3214
#41 0xb617c2c1 in QAbstractButton::clicked (this=0x85f8078, _t1=false) at .moc/release-shared/moc_qabstractbutton.cpp:200
#42 0xb5ea51b9 in QAbstractButtonPrivate::emitClicked (this=0x8709500) at widgets/qabstractbutton.cpp:543
#43 0xb5ea6db4 in QAbstractButtonPrivate::click (this=0x8709500) at widgets/qabstractbutton.cpp:536
#44 0xb5ea7046 in QAbstractButton::mouseReleaseEvent (this=0x85f8078, e=0xbf8b1888) at widgets/qabstractbutton.cpp:1115
#45 0xb5b36323 in QWidget::event (this=0x85f8078, event=0xbf8b1888) at kernel/qwidget.cpp:7521
#46 0xb5ea505e in QAbstractButton::event (this=0x85f8078, e=0xbf8b1888) at widgets/qabstractbutton.cpp:1077
#47 0xb5f4ffc0 in QPushButton::event (this=0x85f8078, e=0xbf8b1888) at widgets/qpushbutton.cpp:662
#48 0xb5adf69c in QApplicationPrivate::notify_helper (this=0x808a330, receiver=0x85f8078, e=0xbf8b1888) at kernel/qapplication.cpp:4057
#49 0xb5ae8311 in QApplication::notify (this=0xbf8b71dc, receiver=0x85f8078, e=0xbf8b1888) at kernel/qapplication.cpp:3759
#50 0xb697db9d in KApplication::notify (this=0xbf8b71dc, receiver=0x85f8078, event=0xbf8b1888) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/kernel/kapplication.cpp:302
#51 0xb7e71adb in QCoreApplication::notifyInternal (this=0xbf8b71dc, receiver=0x85f8078, event=0xbf8b1888) at kernel/qcoreapplication.cpp:610
#52 0xb5ae737e in QApplicationPrivate::sendMouseEvent (receiver=0x85f8078, event=0xbf8b1888, alienWidget=0x85f8078, nativeWidget=0xbf8b31c8, buttonDown=0xb6374a40, lastMouseReceiver=@0xb6374a44)
    at ../../src/corelib/kernel/qcoreapplication.h:216
#53 0xb5b57506 in QETWidget::translateMouseEvent (this=0xbf8b31c8, event=0xbf8b2f1c) at kernel/qapplication_x11.cpp:4446
#54 0xb5b568dd in QApplication::x11ProcessEvent (this=0xbf8b71dc, event=0xbf8b2f1c) at kernel/qapplication_x11.cpp:3442
#55 0xb5b8027a in x11EventSourceDispatch (s=0x808d2c0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#56 0xb563f9c8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#57 0xb5643083 in ?? () from /usr/lib/libglib-2.0.so.0
#58 0xb5643241 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#59 0xb7e9d558 in QEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081397032}) at kernel/qeventdispatcher_glib.cpp:324
#60 0xb5b7f975 in QGuiEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081396984}) at kernel/qguieventdispatcher_glib.cpp:202
#61 0xb7e700fa in QEventLoop::processEvents (this=0xbf8b317c, flags={i = -1081396920}) at kernel/qeventloop.cpp:149
#62 0xb7e7053a in QEventLoop::exec (this=0xbf8b317c, flags={i = -1081396860}) at kernel/qeventloop.cpp:200
#63 0xb5fde6b3 in QDialog::exec (this=0xbf8b31c8) at dialogs/qdialog.cpp:498
#64 0xb708ceca in KoMainWindow::slotConfigureToolbars (this=0x86787c0) at /home/boud/kde/src/koffice/libs/main/KoMainWindow.cpp:1371
#65 0xb7097123 in KoMainWindow::qt_metacall (this=0x86787c0, _c=QMetaObject::InvokeMetaMethod, _id=17, _a=0xbf8b332c) at /home/boud/kde/build/koffice/libs/main/KoMainWindow.moc:144
#66 0xb7e87dc8 in QMetaObject::activate (sender=0x868bce0, from_signal_index=5, to_signal_index=6, argv=0xbf8b332c) at kernel/qobject.cpp:3120
#67 0xb7e88200 in QMetaObject::activate (sender=0x868bce0, m=0xb635c1a8, from_local_signal_index=1, to_local_signal_index=2, argv=0xbf8b332c) at kernel/qobject.cpp:3214
#68 0xb5ad9021 in QAction::triggered (this=0x868bce0, _t1=false) at .moc/release-shared/moc_qaction.cpp:236
#69 0xb5ada59f in QAction::activate (this=0x868bce0, event=QAction::Trigger) at kernel/qaction.cpp:1160
#70 0xb5f39024 in QMenuPrivate::activateCausedStack (this=0x89a4888, causedStack=@0xbf8b3408, action=0x868bce0, action_e=QAction::Trigger, self=true) at widgets/qmenu.cpp:967
#71 0xb5f3f7db in QMenuPrivate::activateAction (this=0x89a4888, action=0x868bce0, action_e=QAction::Trigger, self=<value optimized out>) at widgets/qmenu.cpp:1060
#72 0xb5f40322 in QMenu::mouseReleaseEvent (this=0x916d348, e=0xbf8b3a48) at widgets/qmenu.cpp:2254
#73 0xb6a65475 in KMenu::mouseReleaseEvent (this=0x916d348, e=0xbf8b3a48) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/widgets/kmenu.cpp:456
#74 0xb5b36323 in QWidget::event (this=0x916d348, event=0xbf8b3a48) at kernel/qwidget.cpp:7521
#75 0xb5f425d9 in QMenu::event (this=0x916d348, e=0xbf8b3a48) at widgets/qmenu.cpp:2353
#76 0xb5adf69c in QApplicationPrivate::notify_helper (this=0x808a330, receiver=0x916d348, e=0xbf8b3a48) at kernel/qapplication.cpp:4057
#77 0xb5ae8311 in QApplication::notify (this=0xbf8b71dc, receiver=0x916d348, e=0xbf8b3a48) at kernel/qapplication.cpp:3759
#78 0xb697db9d in KApplication::notify (this=0xbf8b71dc, receiver=0x916d348, event=0xbf8b3a48) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/kernel/kapplication.cpp:302
#79 0xb7e71adb in QCoreApplication::notifyInternal (this=0xbf8b71dc, receiver=0x916d348, event=0xbf8b3a48) at kernel/qcoreapplication.cpp:610
#80 0xb5ae737e in QApplicationPrivate::sendMouseEvent (receiver=0x916d348, event=0xbf8b3a48, alienWidget=0x0, nativeWidget=0x916d348, buttonDown=0xb6374a40, lastMouseReceiver=@0xb6374a44)
    at ../../src/corelib/kernel/qcoreapplication.h:216
#81 0xb5b5778e in QETWidget::translateMouseEvent (this=0x916d348, event=0xbf8b50dc) at kernel/qapplication_x11.cpp:4380
#82 0xb5b568dd in QApplication::x11ProcessEvent (this=0xbf8b71dc, event=0xbf8b50dc) at kernel/qapplication_x11.cpp:3442
#83 0xb5b8027a in x11EventSourceDispatch (s=0x808d2c0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#84 0xb563f9c8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#85 0xb5643083 in ?? () from /usr/lib/libglib-2.0.so.0
#86 0xb5643241 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#87 0xb7e9d558 in QEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081388392}) at kernel/qeventdispatcher_glib.cpp:324
#88 0xb5b7f975 in QGuiEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081388344}) at kernel/qguieventdispatcher_glib.cpp:202
#89 0xb7e700fa in QEventLoop::processEvents (this=0xbf8b533c, flags={i = -1081388280}) at kernel/qeventloop.cpp:149
#90 0xb7e7053a in QEventLoop::exec (this=0xbf8b533c, flags={i = -1081388220}) at kernel/qeventloop.cpp:200
#91 0xb5f42441 in QMenu::exec (this=0x916d348, p=@0xbf8b58d8, action=0x0) at widgets/qmenu.cpp:1993
#92 0xb6a9d135 in KToolBar::contextMenuEvent (this=0x9201020, event=0xbf8b58c0) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/widgets/ktoolbar.cpp:722
#93 0xb5b36a0c in QWidget::event (this=0x9201020, event=0xbf8b58c0) at kernel/qwidget.cpp:7680
#94 0xb5f866ff in QToolBar::event (this=0x9201020, event=0xbf8b58c0) at widgets/qtoolbar.cpp:1193
#95 0xb5adf69c in QApplicationPrivate::notify_helper (this=0x808a330, receiver=0x9201020, e=0xbf8b58c0) at kernel/qapplication.cpp:4057
#96 0xb5ae7edd in QApplication::notify (this=0xbf8b71dc, receiver=0x9201020, e=0xbf8b58c0) at kernel/qapplication.cpp:3846
#97 0xb697db9d in KApplication::notify (this=0xbf8b71dc, receiver=0x9201020, event=0xbf8b58c0) at /usr/src/debug/kdelibs-4.2.88svn973768/kdeui/kernel/kapplication.cpp:302
#98 0xb7e71adb in QCoreApplication::notifyInternal (this=0xbf8b71dc, receiver=0x9201020, event=0xbf8b58c0) at kernel/qcoreapplication.cpp:610
#99 0xb5aea7ee in QCoreApplication::sendSpontaneousEvent (receiver=0x9201020, event=0x873151c) at ../../src/corelib/kernel/qcoreapplication.h:216
#100 0xb5b57cef in QETWidget::translateMouseEvent (this=0x86787c0, event=0xbf8b6f2c) at kernel/qapplication_x11.cpp:4452
#101 0xb5b568dd in QApplication::x11ProcessEvent (this=0xbf8b71dc, event=0xbf8b6f2c) at kernel/qapplication_x11.cpp:3442
#102 0xb5b8027a in x11EventSourceDispatch (s=0x808d2c0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#103 0xb563f9c8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#104 0xb5643083 in ?? () from /usr/lib/libglib-2.0.so.0
#105 0xb5643241 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#106 0xb7e9d558 in QEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081380632}) at kernel/qeventdispatcher_glib.cpp:324
#107 0xb5b7f975 in QGuiEventDispatcherGlib::processEvents (this=0x808a310, flags={i = -1081380584}) at kernel/qguieventdispatcher_glib.cpp:202
#108 0xb7e700fa in QEventLoop::processEvents (this=0xbf8b7190, flags={i = -1081380520}) at kernel/qeventloop.cpp:149
#109 0xb7e7053a in QEventLoop::exec (this=0xbf8b7190, flags={i = -1081380456}) at kernel/qeventloop.cpp:200
#110 0xb7e729e9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#111 0xb5adf517 in QApplication::exec () at kernel/qapplication.cpp:3526
#112 0xb7f9590d in kdemain (argc=1, argv=0xbf8b72d4) at /home/boud/kde/src/koffice/krita/main.cc:44
#113 0x08048872 in main (argc=) at /home/boud/kde/build/koffice/krita/krita_dummy.cpp:3

I noticed a similar effect with split views,  switching to one view and another causes a increase of the docker's width

Fixed in Krita 2.1 Beta2