"Show More" in connections pane jumps to top

[jmcphers]

System details

RStudio Edition : Desktop
RStudio Version : 1.1.423
OS Version      : MacOS 10.13.3
R Version       : 3.4.2

Steps to reproduce the problem

1. Click New Connection.
2. Connect to a data source which has several hundred objects at the top or first level.
3. Scroll down to the last displayed object and click Show More.

Describe the problem in detail

Clicking Show More sends you back to the top of the list.

Describe the behavior you expected

It should maintain your scroll position.

[jmcphers]

It turns out that this only reproduces in 1.1. The problem is here:

rstudio/src/gwt/src/org/rstudio/studio/client/workbench/views/connections/ui/ObjectBrowser.java

Lines 141 to 144 in 9f935f6

	objects_ = new CellTree(objectsModel_, null, RES, MESSAGES);
	// create the top level list of objects
	objects_.setDefaultNodeSize(Integer.MAX_VALUE);

Once the cell tree has been constructed, you can't change the defaultNodeSize of the root node. This is fixed in 1.2, where we supply it in the constructor instead.

rstudio/src/gwt/src/org/rstudio/studio/client/workbench/views/connections/ui/ObjectBrowser.java

Lines 143 to 144 in b5128ea

	// create new widget
	objects_ = new CellTree(objectsModel_, null, RES, MESSAGES, Integer.MAX_VALUE);

So on 1.2 users don't get a "Show More" at all -- they just see all of the objects, all of the time.

Unfortunately the "Show More" button doesn't emit any events and it's difficult to tell if it's been clicked. The best we could do would be to attach our own click handler to the CellTree; if we receive a click destined for Show More we could save the scroll position and defer a restore.