I've reported this bug in Debian https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=774377 but it appears that it is a general KDE bug, not Debian one. So I report it again here.

When the mouse is above the current file, this filename is displayed
white on white background and so is invisible.

See the first file (after the folder auth/) in the screenshot.
It is a white spot.

Screenshot:
https://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=shot.png;att=1;bug=774377

-- System Information:
Debian Release: 8.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable')
Architecture: i386 (x86_64)

Kernel: Linux 3.10-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)

Versions of packages dolphin depends on:
ii  kde-runtime        4:4.14.2-2
ii  libbaloocore4      4:4.14.2-1
ii  libbaloofiles4     4:4.14.2-1
ii  libbaloowidgets4   4:4.14.0-1
ii  libc6              2.19-13
ii  libkactivities6    4:4.13.3-1
ii  libkcmutils4       4:4.14.2-4
ii  libkdecore5        4:4.14.2-4
ii  libkdeui5          4:4.14.2-4
ii  libkfile4          4:4.14.2-4
ii  libkfilemetadata4  4:4.14.0-1+b2
ii  libkio5            4:4.14.2-4
ii  libknewstuff3-4    4:4.14.2-4
ii  libkonq5abi1       4:4.14.2-1
ii  libkparts4         4:4.14.2-4
ii  libphonon4         4:4.8.0-4
ii  libplasma3         4:4.14.2-4
ii  libqt4-dbus        4:4.8.6+git64-g5dc8b2b+dfsg-2+b1
ii  libqt4-xml         4:4.8.6+git64-g5dc8b2b+dfsg-2+b1
ii  libqtcore4         4:4.8.6+git64-g5dc8b2b+dfsg-2+b1
ii  libqtgui4          4:4.8.6+git64-g5dc8b2b+dfsg-2+b1
ii  libsolid4          4:4.14.2-4
ii  libstdc++6         4.9.1-19
ii  libxrender1        1:0.9.8-1+b1
ii  phonon             4:4.8.0-4

Versions of packages dolphin recommends:
ii  ruby  1:2.1.0.4

Versions of packages dolphin suggests:
pn  kdesdk-dolphin-plugins  <none>

Reproducible: Always