Oh leszek, thank you thank you!! How wonderful. This FIXED the problem!!
With Emacs as my ROOT GTK - GTK3 Theme, my Synaptic now looks just like it did in Mint 17.x KDE4, ie, it is now once again pleasant to use. I'm so grateful for your help.
This pic is my "new" Synaptic, in Maui, not Mint [heehee] - now there's not an ugly microscopic nearly-invisible blue tick anywhere:
With Emacs as my ROOT GTK - GTK3 Theme, my Synaptic now looks just like it did in Mint 17.x KDE4, ie, it is now once again pleasant to use. I'm so grateful for your help.
This pic is my "new" Synaptic, in Maui, not Mint [heehee] - now there's not an ugly microscopic nearly-invisible blue tick anywhere: