Deep transformation of Win2000 "position bar"

Compared to previous Windows, the WIN2K/XP user interface has been greatly improved, making it much easier for users to use Windows. For example, Active Desktop is based on HTML, which is a huge change for Windows NT 4.0 users. Whether you like it or not, the new user interface gives experienced users the opportunity to customize the desktop, enabling people to do their daily work more efficiently. The Open dialog box is one of the most commonly used dialog boxes, and in the win 2K/XP user interface, it adds a "position bar", and this article discusses how to customize this location bar.
The description of this article is mainly for win 2K, but the rationale is also applicable to XP, and the differences will be noted separately.
First, open dialog box
You may have noticed that some software runs under WIN2K/XP, and their Open dialog box differs from WIN9X/NT 4.0. Figure one shows the standard Win2K "open" dialog box, which is displayed by clicking on the "File/Open" menu in Notepad. This dialog box adds something to the previous operating system: a vertical button bar is added to the left of the window. The Win2K SDK documentation refers to this button bar as the "position bar" (Places bar).




Figure I: Standard Win2K "open" dialog box
The role of the location bar is to allow users to use only one mouse click to reach the frequently used folders. The WIN2K/XP position bar contains up to 5 buttons, each pointing to a system folder. Click on any button and the Open dialog box immediately displays the contents of the corresponding folder.
The default location bar provides a single button for each of the following folders: History, Desktop, My Documents, my computer, My Network Neighborhood. The History folder records the most recent files and folders used by users, and the History folder is the first place to view if you want to access the most recently used files or folders. Many users also frequently use the other four folders.
The default location bar configuration contains the most commonly used folders for most users, and meets the needs of most users. However, this default configuration may not be consistent with your work habits, and you will need to customize it.

Second, custom location bar
The folders for the location bar are not explicitly listed, either in the registry or anywhere else. Therefore, WIN2K/XP always use the standard location bar unless you manually or automatically create a new set of locations by using a program.
The location bar is a system-level resource. Once a set of positions is assigned to the location bar, all WIN2K/XP software will use this set of locations. This restriction means that you cannot specify a configuration for Notepad's location bar, and another configuration for the brush's position bar, and that all programs running under WIN2K/XP share the same set of locations-whether this set of locations is standard or custom. (The office exception, which can have a different set of locations, is discussed in detail later).
To specify a new set of folders for the location bar, the first step is to tell the system that you are not ready to use the default 5 locations. Create Hkey_current_user\software\microsoft\windows\currentversion\policies\comdlg32\placesbar registry subkeys (Generally, The Plicies subkey may already exist, but the ComDlg32 subkey needs to be created by itself. After you create the subkey, you can see that the position bar of the Open dialog box has become blank. The Placesbar key tells Win2K you don't want to use a standard location combination, but you haven't specified your own configuration at this point.
The Placesbar subkey contains up to 5 registered entries, from Place0 to Place4. WIN2K/XP will not endorse or correctly handle Place5, Place6, or other name registration keys. The position should be specified sequentially, for example, you cannot set Place0, Place2 Miss Place1. If the location of the registry settings is messy and incomplete, the location bar displays the icon and folder name in unpredictable order.
When you add location information to a Placesbar subkey, the way you specify the folder is to provide the full pathname of the folder as a string. The type of registration data is REG_SZ (if the name of the folder is used in the environment variable, it should be REG_EXPAND_SZ).
You can specify the system folder as the location on the location bar in the registration information. System folders tend to have long paths and are not easy to remember (for example, can you immediately say the full path to My Documents?). If you want to designate My Documents or favorites as a location, you can use a numeric ID that is not specific to your system, instead of using its full pathname. Microsoft referred to this ID as csidl. Table one lists the IDs of the Win2K common system folders. For such folders, you can create a registered entry of type REG_DWORD under the Placesbar subkey and specify an ID.
Table one: Win2K system folders and their IDs