I've been playing around with SpaceFM 1.0.6 for past couple of hours and found that with one exception it works perfectly in SliTaz 5.0. The exception is that it seems impossible to pull the SpaceFM window wider or narrower from its left or right edges. But as one can still pull the top and bottom edges as well as the four corners, this is of no importance at all. The problem may also have to do with the fact that I ran the test from the current live CD with the graphic card unconfigured ... who knows.
I wasn't so happy with the direction the LXDE desktop took a couple of years ago. To me it was getting ever more bulky, complex, in-transparent, with tons of new dependencies and with a shared library between PCMan and LXPanel. It was in my opinion no longer a light-weight desktop and it certainly was no longer as fast and snappy as it used to be not so long ago. What's more, when one compares the iso sizes of various distros, there's not so much difference any more between the LXDE, XFCE and Gnome versions of the distros.
But with the latest version of SpaceFM now available in SliTaz and with my diy version of LXPanel 0.6.2, things look much brighter as I can get rid of the SpaceFM 1.0.5 version I nicked from Slackware and remove more superfluous stuff. Thanks again Hans-Günter, this was just what was needed in SliTaz.
P.S.: if there should be more demand for this, maybe LXPanel 0.6.2 could also be added to the repo? It's the last independent version of the panel, without a shared library with PCMan.