The Dictionary preferences pane collects a number of options having to do with the appearance and behavior of dictionary windows and explorers.

Opening:

Governs what should happen when you open a dictionary. The issue here is that a dictionary window has three possible states, so which one should appear when the window opens? Your choices are:

Show Dictionary

The dictionary window displays the terminology list and the info pane.

Show Object Model

The dictionary window displays the object model diagram and the info pane.

Show Explorer

The dictionary window displays the application explorer.

Remember state

The state that appears is the state that was showing when the dictionary window for this application was closed previously.

Dictionaries List Options

Large icons indicate running applications

If checked, then in some places where the dictionaries list appears (the dictionary window, the File > Open Dictionary menu), running application icons and the Scripting Additions icon are large.

Only search Applications folder for dictionaries

If checked, then when Script Debugger populates the All section of its dictionaries list at launch time, it doesn’t look outside the Applications folder. Applications that Script Debugger subsequently meets for other reasons (because they are running, or recent, or because you open their dictionaries) will be added to the list as well. Depending on how your hard disk is organized, this can reduce the overall size of the dictionaries list.

Explorer Options:

Show contents of list and record values

Controls how outliners display the Value column for lists and records. if checked, the value is a literal list similar to Source view; if unchecked, the value is shown as the item count (e.g., “list of 2 items”).

Show description tooltips

If checked, a tooltip appears when the mouse is hovered over the Element/Property column of an outliner, displaying the comment from the corresponding dictionary entry.

Show value tooltips

If checked, a tooltip appears when the mouse is hovered over the Value column of an outliner, displaying the comment from the corresponding dictionary entry for that value’s class if there is one.

Render HTML string values as HTML page

If checked, then Best view for an HTML string is rendered as in a Web browser.

Show N elements at a time

The number of elements to be shown initially in an outliner when the elements of an element collection are displayed. If there are additional elements, a Show More button appears. Limiting the number of elements displayed at a time reduces the number of Apple events that Script Debugger must send.

Access Elements by Index / ID / Name

The default specifier for initially accessing elements of an element collection for display in an outliner. You can change the specifier with the pop-up menu in the outliner. If the requested specifier fails (because the application doesn’t respond to it), Script Debugger automatically falls back on a different specifier.

Dictionary Caching:

Cache generated dictionaries

If checked, Script Debugger maintains cached copies of application dictionaries. This makes display and searching of dictionaries faster, because one an application’s dictionary has been cached, there is no need to launch that application in order to obtain its dictionary. Most users should not need to uncheck it.

Clear Cache

Clears Script Debugger’s internal cache of known application dictionaries.

Concerning why you might want to uncheck “Cache generated dictionaries”, or why you might want to click Clear Cache, read here.