Is it possible to select multiple models and drag all of them as a group?

I talked to Marianna on the phone about this issue, she was able to drag and drop, as well as scroll while dragging, when I had her switch the Data module scene model to Displayable and build the tree there.

Nicole,
As discussed, Julien will be providing you support through email.

svn 20352 should fix the "drag past the end of the visible tree" problem:
d->ModelHierarchyTreeView->setFitSizeToVisibleIndexes(false);

Enabled selection of multiple models at once (selection mode set to QAbstractItemView::ExtendedSelection), with delete and rename working.
Still to do: get dropping working more robustly for single models, and get it working for multiple models.

Clicking between models to select will frequently change the visibility state of the model and other models in the hierarchy. for example, set one model to visible and the other invisible, then click the visibility button for the first model. The visibility state of both models will be switched.

Also, it seems that it is no longer possible to change colors and opacity from the hierarchy list slider/button. In the case of colors, the selector pops up, but the color choice is not applied.

in Slicer 4.1.0-2012-06-26 the Model Hierarchy View window does not fit to the size of the expanded tree.

Julien figured out why drag and drop in the models module wasn't working well (icon comparison via cache keys changed to using a decoration role). svn 20604 fixes it for me.

Isiah: I havne't been able to reproduce your colour setting bug, is it still an issue?

After discussion, Julien explained that in Qt, using the open/close state of the treeview is not 'meant' to control aspects of the underlying model.

Instead, we discussed adding an "override" checkbox (or similar) to parent nodes -- this would make it explicit for users. The rule would be that the highest parent in the hierarchy that has the override property should define the view of the children (and grandchildren...)

Checkbox is controlling the "Expanding" property as of r20768

Nonetheless there are inconsistencies at the MRML level:
a) GetUnExpandedParentNode: see failing test from r20766.
b) DisplayModifiedEvent: see failing test from r20766.
c) model Visibility is not behaving the same way colors behave (qMRMLTreeView is calling vtkMRMLModelHierarchyLogic::SetChildrenVisibility)
d)(bonus): Rename "UnExpanded" into "Collapsed"
e)(bonus): Add utility methods (GetColor/Visibility or GetCollapsedDisplayNode)... in vtkMRMLDisplayableHierarchyNode that returns the the collapsed hierarchy display node properties.

I am not quite clear what the checkbox does. I tried it on 8-15 nightly on linux.
it would be good to have a tooltip

b - svn 20825, test vtkMRMLDisplayableHierarchyNodeTest1 now passes.

a) adding a few print outs into the test, this is correct (or at least consistent with Slicer3 behaviour): when there is a hierarchy tree multiple levels deep and sub hierarchies are collapsed as well as the top level hierarchy, the collapsed sub hierarchy closest to the model is returned by GetUnExpandedParentNode.

So current behaviour is:
H1
m1
H2
m2
If H2 and H1 are collapsed, model m2 will be displayed using the color from the display node associated with H2.
If only H1 is collapsed, models m1 and m2 will be displayed using the color from the display node associated with H1.

I agree that it's confusing, pointing the email thread back to the bug to get feedback on changing it.

c) is related to a), what's the desired behaviour, to just use the model hierarchy display node properties for the models or to actually change the model display nodes under the hierarchy (currently it's inconsistent, visibility is done differently than color). Waiting on feedback.

updated the failing test vtkMRMLDisplayableHierarchyNodeDisplayPropertiesTest to give expected values, svn 20874.

Talking to Ron on the NAMIC Eng t-con:
Re: comment 0005706, he wants m2 to be coloured by H1 if both H1 and H2 are collapsed.
Re: comment 0005707, the changing of the model visibility is desired, but we need a more intuitive UI to make it clear what's going on.

svn 20898 fixes getting the UnExpanded parent node, and renames it to Collapsed.

Marianna need the tree to adjust to the number of nodes and drag and drop working past the end of the window.

Moved the checkbox in the color column in r20991

Moved the checkbox in own column in r20999

it would be good to have all colors stay in a single column. See image why this does not work.

Colors staying in a single column has been fixed in r20999 (see comment 0006115)

As of r24719, unable to reproduce the problem.