Bug 166494

Version:           1.9.51 (using 4.0.4 (KDE 4.0.4 >= 20080505) "release 15.1", compiled sources)
Compiler:          gcc
OS:                Linux (i686) release 2.6.25.5-1.1-pae

From the main menu, select: Settings->Configure Filters
Click on New, select criteria. Select 'Move to Folder' as action. Click on folder button (button has folder icon and no label). "Select Folder - KMail" dialog box opens, containing single entry "Local Folders". 
Double-click on "Local Folders" or single click on [-] (normally used to expand/collapse tree) will cause crash.

Note this also crashes when using "Message->Create Filter->Filter on From" from main menu, and the same button is used to select the folder to move messages into (same "Select Folder - KMail" dialog box opens etc.

Note that the tree is not populated with the Local Folders in the "Select Folder -KMail" dialog box.