Use Modify|Fix to fix (or 'repair') the selected directory/files. This option is only applicable for certain, unusual working copy states and provides support to handle them:
SVN repositories and working copies are in general case-sensitive. This can cause problems when working on a case-insensitive operating system, like Microsoft Windows or certain file systems on Apple Mac OS and changing the file name's case (upper-case to lower-case, etc.). Because of SVN's working copy format and the pristine copies, it's technically not possible to handle such a file name case change.
One solution is to avoid this situation by only performing file name case changes on an operating system which supports case-sensitive file names or directly in the repository, by using the Repository Browser.
Anyway, a file name case change may happen on a case-insensitive operating system, e.g. because of defect software tools, etc. SmartSVN detects such invalid changes and puts the file into case-changed file state, see Primary File States. Fix will now change back the file name case to its original form as found within the pristine copy, resolving this problem.
A nested root (see Primary Directory States) is a working copy within another working copy which is not related to this parent working copy. SVN commands ignore such nested roots, they are simply treated as unversioned directories.
Nested roots are typically resulting from moving a directory from one location to another one, without using appropriate SVN commands, like Move. This leaves a missing directory at its original location and introduces nested root at its current location.
Fix offers following solutions for nested roots, depending on their origin: