Bugfix for removing cut filter when switching to splatterplot

[AntonPiccardoSelg]

This fixes issue (11602)[http://trac.mantidproject.org/mantid/ticket/11602]

For testing:
Please find a sample workspace attached to the original ticket.

1. Open the sample workspace into the VSI
2. Switch to the standard view (if not already in it)
3. Apply the cut filter
4. Switch to the Splatterplot view
5. Confirm that Mantid does not crash

[FedeMPouzols]

This also works well. It doesn't crash and behaves well. I'll wait for the windoze build to double-check but I think there shouln't be any issues there.

[FedeMPouzols]

Oops, but if you add the following two steps after step 5, you'll get a crash. This looks unrelated to the ticket this PR addresses, and has more to do with the "pick mode". Staying in the Splatterplot view:

• Click on Override PC
• Click on "Pick Mode"
  After this you'll get a segfault. An small white cross appears in the center of the view but before you can do anything it crashes. This is the trace that I could get:

#0  0x00007fffc5a77b30 in pqProxy::getProxy() const () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqCore-pv4.3.so.1
#1  0x00007fffc5a85751 in pqScalarsToColors::getScalarRange() const () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqCore-pv4.3.so.1
#2  0x00007fffc6e5130f in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::setMinBufferAndMaxBuffer(pqPipelineSource*, double&, double&) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#3  0x00007fffc6e51967 in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::getStandardColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#4  0x00007fffc6e51b98 in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::getColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#5  0x00007fffc6e57d75 in Mantid::Vates::SimpleGui::ColorUpdater::autoScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#6  0x00007fffc6e86ea4 in Mantid::Vates::SimpleGui::ViewBase::setAutoColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#7  0x00007fffc6e59993 in Mantid::Vates::SimpleGui::MdViewerWidget::checkForUpdates() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#8  0x00007fffc6e8a155 in Mantid::Vates::SimpleGui::MdViewerWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#9  0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#10 0x00007fffc665dd9a in pqPropertiesPanel::apply() () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqComponents-pv4.3.so.1
#11 0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#12 0x00007fffc6e81698 in Mantid::Vates::SimpleGui::SplatterPlotView::onPickModeToggled(bool) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#13 0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#14 0x00007ffff4d62c32 in QAbstractButton::toggled(bool) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#15 0x00007ffff4aa482d in QAbstractButton::setChecked(bool) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#16 0x00007ffff4aa43e3 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#17 0x00007ffff4aa4534 in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4

I'm not sure if there's any ticket about this? If not maybe we need to open one for this.
Well, actually you just need to open a workspace, switch to the "scatterplot view", and click "pick mode". You'll get a very similar crash, like this:

#0  0x00007fffc5a77b30 in pqProxy::getProxy() const () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqCore-pv4.3.so.1
#1  0x00007fffc5a85751 in pqScalarsToColors::getScalarRange() const () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqCore-pv4.3.so.1
#2  0x00007fffc6e5130f in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::setMinBufferAndMaxBuffer(pqPipelineSource*, double&, double&) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#3  0x00007fffc6e51967 in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::getStandardColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#4  0x00007fffc6e51b98 in Mantid::Vates::SimpleGui::AutoScaleRangeGenerator::getColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#5  0x00007fffc6e57d75 in Mantid::Vates::SimpleGui::ColorUpdater::autoScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#6  0x00007fffc6e86ea4 in Mantid::Vates::SimpleGui::ViewBase::setAutoColorScale() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#7  0x00007fffc6e59993 in Mantid::Vates::SimpleGui::MdViewerWidget::checkForUpdates() () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#8  0x00007fffc6e8a155 in Mantid::Vates::SimpleGui::MdViewerWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#9  0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#10 0x00007fffc665dd9a in pqPropertiesPanel::apply() () from /home/fedemp/build-mantidnightly/build-paraview/lib/libvtkpqComponents-pv4.3.so.1
#11 0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#12 0x00007fffc6e81698 in Mantid::Vates::SimpleGui::SplatterPlotView::onPickModeToggled(bool) () from /home/fedemp/test/build-mantid/bin//libMantidVatesSimpleGuiViewWidgets.so
#13 0x00007ffff39def4c in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#14 0x00007ffff4d62c32 in QAbstractButton::toggled(bool) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#15 0x00007ffff4aa482d in QAbstractButton::setChecked(bool) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4

It seems to happen with other Histo and Event workspaces. So it looks like there's something wrong in "pick mode".

[FedeMPouzols]

Yes, the last commit fixed this last crash issue for me.

[FedeMPouzols]

All is well. This PR closes the ticket issue + the "pick mode" issue.