Introducing the Reference Explorer

Back in the 2.1.x announcement post over a whole year ago, one of the bullet points about the upcoming roadmap said we were going to “make you never want to use the VBE’s Project References dialog ever again“; it took a bit longer than expected, but as far as we can tell, this feature does exactly that.

If you’ve been following the project on social media recently, you already know that the next version of Rubberduck will introduce a very exciting, unique new feature: the Reference Explorer dialog, and the addition of a references node in the Code Explorer tree.


Since forever, adding a reference to the active project in the VBE is a rather… vanilla experience. Functional, but somewhere between bland and tedious.

What’s wrong with it?

Regardless of what we think of the very 1998-era buttons docked on the side, the dialog works. There’s a list of available libraries (sorted alphabetically), we can browse for unlisted ones, cancel or accept changes, and the libraries that are selected when the dialog is displayed, are conveniently shown at the top of the list!

On a closer look though…

The vanilla-VBE project references dialog
  1. The list of available libraries has the available libraries listed in alphabetical order. You can’t resize the dialog to show more, but you get first-key search. The Scripting runtime’s library name starts with “Microsoft”… which happens to also be the case for a few other libraries; this makes the extremely useful Scripting.Dictionary and Scripting.FileSystemObject classes pretty much hidden until you stumble upon a blog post or a Stack Overflow answer that introduces them.
  2. The selected libraries show up at the top of the list, in priority order. Locked libraries are stacked at the top. You use the up/down arrow buttons to move the selected library up or down, but you can’t move the locked ones.
  3. The priority buttons are used to determine the identifier resolution order; if an identifier exists in two or more libraries, VBA/VB6 binds to the type defined in the library with the highest priority. There’s no visual cue in the list itself to identify the locked-in type libraries, so the Enabled state of these buttons is used to convey that information: you can’t move the locked-in, default references.
  4. The bottom panel is useful… but the path gets cropped if it’s longer than the rather narrow dialog can fit, and you can’t select or copy the text. The actual library version number isn’t shown.

Visual Studio

Let’s take a look at what adding a project reference using the latest version of Microsoft Visual Studio feels like:

The Microsoft Visual Studio 2017 Reference Manager dialog

The dialog can be resized, search is no longer limited to a single character, but still limited to the beginning of the [Name]. The library info is now richer; it moved to the right side, and a panel on the left side determines the contents of the list. Other than that, besides a new [Version] column and a nice dark theme, …the mechanics are pretty much the same as they were 20 years ago: check boxes in a list. Priority is no longer relevant in .NET though – namespaces fixed that.


This screenshot was taken shortly before the pull request was opened:

The Rubberduck ‘Add/Remove References’ dialog (work in process: release build may differ)
  1. Available libraries appear in a list on the left-hand side of the dialog. Like in Visual Studio, the version number appears next to the library name, and the list is sorted alphabetically. There is no checkbox: instead, the selected library can be moved into the list of referenced libraries.
  2. Referenced libraries appear in a list on the right-hand side of the dialog. Since there is no checkbox, the selected library can be moved back into the list of available libraries.
  3. Priority up/down buttons appear for the selected referenced library, unless it’s locked.
  4. Icons differentiate locked libraries, libraries that were already referenced when the dialog was shown, and libraries that were newly added. In the list of available libraries, recent and pinned libraries have an icon too.
  5. Search works on a “contains” basis, and matches the library name, description, and path. It immediately filters the list of available libraries.
  6. Tabs for quickly accessing type libraries recently referenced, or pinned libraries, or registered. Host-specific project types are in a separate tab, as applicable.
  7. Bottom panel displays the full name and path of the selected type library. The text can be selected and copied into the clipboard.
  8. Browse button allows referencing any project/library that isn’t listed anywhere. If a library can’t be loaded, it will appear in the list as a broken reference, before it’s even tentatively added to the project.

If you haven’t seen it in action yet, here’s a sneak peek:

Of course that’s just the beginning: layout is not completely final, drag-and-drop functionality remains to-do, among other enhancements.

A first iteration of this feature will likely be merged some time next week, and since this is a major, completely new feature, we’ll bump the minor version and that will be Rubberduck 2.4.0, to be released by the end of 2018…

…not too long after the imminent 2.3.1 hotfix release.

If you think this is one of the coolest things a VBE add-in could possibly do, you’re probably not alone. Share the news, and star us on GitHub!


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