LXDE (Lightweight X11 Desktop Environment) was created in 2006 by Hong Jen Yee (PCMan) from Taiwan as an energy-efficient, lightweight desktop for older hardware. Built on GTK+ 2, it powered the default desktop of Lubuntu and Raspberry Pi OS. But as GNOME moved to GTK+ 3 with its heavier resource requirements, LXDE faced a dilemma: follow GTK's increasingly heavyweight direction or switch to something else.

PCMan began porting LXDE to Qt, believing Qt offered a better path for lightweight desktop development. Meanwhile, a completely separate project called Razor-qt had launched in 2010 with the same goal: building a lightweight desktop environment using Qt. The two projects were solving the same problem with the same toolkit, duplicating effort.

On July 21, 2013, the Razor-qt and LXDE teams announced they would merge. The combined project, named LXQt, would take the best components from both projects and build a unified lightweight Qt desktop. It was a rare example of two open-source projects recognizing duplication and choosing collaboration over competition.

The transition wasn't instant. LXDE (the GTK version) and LXQt coexisted for years, with some distributions shipping LXDE while others adopted LXQt. Lubuntu switched from LXDE to LXQt starting with version 18.10 in 2018. LXDE itself hasn't been formally discontinued but development is minimal.

LXQt has matured into a capable lightweight desktop, though it occupies a challenging niche between the ultra-minimal window managers and the full-featured XFCE. Recent releases have modernized the look while keeping resource usage low, and the project maintains steady if unglamorous development.

LXQt is one of the few examples of two open-source projects voluntarily merging rather than competing. It preserved the lightweight desktop niche during a period when major desktop environments were becoming increasingly resource-hungry, and it demonstrated that toolkit migration (GTK to Qt) can be a valid reason for a soft fork.