Startup Applications - Custom Command Browse leaves spaces in file paths

[MrAce100]

 * csd version - 5.2.0-2
 * Distribution - Manjaro Linux
 * Graphics hardware *and* driver used - Intel Corporation 3rd Gen Core processor Graphics Controller, video-linux
 * 32 or 64 bit: 64

Issue
If a space is present in the file path, executables or scripts selected via the "Browse" option when creating a "Custom Command" startup command will not run correctly if not modified. Backslashes must be manually added before each space for the script to start at startup as expected.

Steps to reproduce
Make a bash script (with something like echo hello > ~/Desktop/works.txt in it) with a space in its name. Open the "Startup Applications dialog and create a "Custom Command", Click browse, select the bash script, relog.

Expected behaviour
Backslashes are automatically added to the .desktop file, or the user is notified the command will not work unless backslashes are manually added.