Compare Two Files - Compares two files and shows the differences between them. When this option is selected, after you click OK on this dialog to start the comparison, the interactive Diff dialog is displayed, allowing you to preview the differences one-by-one before committing.

If the option on the Options tab, Instead of an interactive dialog, output one buffer with the differences labeled, is checked, a buffer with the differences between the two files marked up will be displayed instead.

Compare Two Folders - Compares two directories or directory trees, and shows which files do not match. Select Recurse into subdirectories to search subdirectories recursively. Click Previous diff to load a diff state file (.dif), restoring the saved state of a multi-file diff session.

Path 1, Path 2 - When comparing files, set Path 1 and Path 2 to file names. When comparing folders, set Path 1 and Path 2 to directory names. If the file names only differ by path, you only need to specify a directory for Path 2.

You can use the drop-down list to select a previously used item to compare. To browse for a file or directory, click the Ellipses button. Click the B button to select an open buffer.

Compare type - the second drop-down list lets you select the type of comparison to run. Select one of the following:

Use file on disk - Select this option to diff the file on disk and not the copy in memory.

Toggle automatic directory mapping - when on, Path 2 is calculated based on other Path 2 directories used with the current Path 1 directory. The icon contains a little, red 'x' when off.

Copy path - copies the path from Path 1 to Path 2 or vice versa. The direction of the copy is indicated by the arrow in the icon. When the arrow is pointing down, it will copy from Path 1 to Path 2. The direction is controlled by the location of the cursor, which designates the origin of the copy.

Swap paths - click on this button to swap the paths from Path 1 to Path 2.

Toggle Code Diff - turns Source Diff on or off. When Source Diff is off, the icon contains a small, red 'x'. Source Diff is on by default.

Filespecs - Enter a space-delimited list of wildcard file specifications to difference. For example, enter "*.c *.cpp *.h" to difference all files with .c, .cpp, and .h extensions.

Exclude filespecs - Enter a space-delimited list of wildcard file specifications to be excluded from the differencing. For example, enter junk* test* to exclude all files with names beginning with the words "junk" or "test". To exclude a specific directory, provide the full path. To exclude any subdirectory with a particular name, put a slash at the end of the name. For example, enter ".svn/" to exclude all subdirectories named ".svn" wherever they occur.

Expand tabs into spaces before comparing - When selected, tabs are expanded to the appropriate number of spaces before lines from each file that is compared.

Ignore leading spaces before text on each line - When selected, differences in leading spaces of lines are ignored.

Ignore trailing spaces after text on each line - When selected, differences in trailing spaces at the end of lines are ignored.

Ignore all spaces in file - When selected, differences in spacing between characters in lines are ignored.

Compare files case insensitive - When selected, differences in character casing are ignored.

Do not compare newline characters - When selected, differences in end-of-line characters are ignored. This is useful when comparing UNIX-formatted files with DOS-formatted files.

Skip comments at the beginning of the file - When selected, leading comments are ignored. This is useful if you are using a version control system that automatically inserts comment file headers.

Instead of an interactive dialog, output one buffer with the differences labeled - When selected, a new buffer is created that contains color-coded difference output. You can edit the output buffer. When this option is not selected, the Diff dialog box opens displaying the two files side-by-side and the differences are color-coded.

Source Diff - Determines whether Code Diff is used. Source Diff compares the code temporarily reformatting the code from Path 2 to match the format in Path 1. This is very useful when one version has been both beautified and contains other meaningful changes. Source Diff can also be toggled by an icon on the diff dialog.

Date and Size Optimization - These options control how DIFFzilla analyzes multi-file diffs.

Show gauge during diff - When selected, a gauge control will show various processing statistics while you wait for the differences output to complete.

Jump to next diff after copy block - When selected, the cursor is moved to the next difference when you apply changes from one file to the other. For example, after clicking Block on the Diff dialog box, the tab moves to the next difference. This option has no effect on interleaved output.

Automatic directory mapping - When selected, the Path 2 text box is automatically updated when you type a directory in the Path 1 text box.

During multi-file diff, automatically close after last difference - When selected, clicking Next Diffon the Diff dialog box when there are no more differences, triggers the Close button on that dialog box.

When closing multi-file diff, do not prompt to save results - suppresses the prompt to save results after a multi-file diff.

Put buttons at top of diff dialog - When selected, the buttons that control operations such as Next Diff, Prev Diff, and Block, are displayed at the top of the Diff dialog box.

Launch multi-file diffs in a separate process - When selected, source trees are diffed in a separate process so you can continue working.

Expert mode setup dialog - When this is on, Compare Two Files or Compare Two Folders will be selected automatically based on whether the paths contain folder names or file names. This was the how SlickEdit 2008 and previous versions worked.

Number of sessions automatically saved - Determines the number of sessions automatically saved under Recent Sessionsin the Sessions tree. The default value is 10.

Starting position - Determines whether to place the cursor at the top of the file or at the first difference when the Diff dialog box is displayed. This option has no effect on interleaved output.

Dialog initialization - Determines whether the DIFFzilla dialog box restores previous dialog settings (history) or just places the current buffer name into the Path 1 text box. Press F7/ F8 to restore the previous next dialog settings, respectively.