What you’re running into is caused by KDE Plasma’s newer Quick Tile behavior introduced around Plasma 5.27 and continued into Plasma 6.x.
Older Plasma versions behaved more like classic Windows Aero Snap: snapping a window to the left or right edge was mostly just a temporary positioning shortcut. After snapping, the window still behaved like a normal floating window and could be resized independently without affecting future snaps.
Modern Plasma changed this behavior.
Quick-tiled windows now participate in a persistent split-layout system managed by KWin. Once two windows are snapped side-by-side, KWin treats them as connected tiled regions rather than completely independent floating windows.
Because of that:
- resizing one snapped window also resizes the adjacent snapped window,
- shared borders become linked or “magnetic,”
- modified split ratios are remembered,
- future quick-snapped windows reuse the modified ratio instead of resetting to exact 50/50,
- and snapped windows no longer behave like freely floating windows until detached from the tiled state.
This is exactly why your workflow feels awkward.
Your workflow is:
1. snap a window,
2. get roughly the right placement,
3. manually fine-tune the width afterward.
Modern Plasma instead assumes:
1. snap a window,
2. maintain a persistent tiled relationship afterward.
That design difference is the root of the issue.
A particularly important KWin regression report documented this exact behavior:
after resizing a quick-tiled window once, all future quick-tiled windows inherit the modified split ratio instead of returning to equal halves.
Other users also repeatedly reported:
- windows becoming “glued together,”
- inability to independently resize snapped windows,
- persistent asymmetric layouts,
- quick-tile layouts affecting other desktops/workspaces,
- and ultrawide monitor workflows becoming significantly less practical.
Current workarounds people commonly use include:
- dragging the window slightly away from the edge first to detach it from the tiled state,
- resetting tile layouts manually,
- deleting custom tiles from the Meta+T tiling editor,
- disabling edge tiling behavior,
- using Meta+drag or Meta+right-click resizing,
- or avoiding persistent tiling workflows entirely.
However, none of these fully restore the older “snap first, freely resize afterward” behavior from pre-5.27 Plasma.
The issue is fundamentally tied to KWin’s newer tiling-oriented design philosophy rather than a simple resize bug.