How to correctly refresh SDL2 window after resizing - c

Question

I wrote a little SDL2 app that reacts on resizing by rearranging its contents. It works quite nice on Windows 10, but not on my Linux machine.
Here's the MCVE that (hopefully) reproduces the problem:
#include <SDL2/SDL.h>
int main(int argc, char **argv)
{
SDL_Init(SDL_INIT_VIDEO);
SDL_Window *w = SDL_CreateWindow("MCVE",
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 250, 250,
SDL_WINDOW_ALLOW_HIGHDPI|SDL_WINDOW_RESIZABLE);
SDL_Renderer *r = SDL_CreateRenderer(w, -1, SDL_RENDERER_ACCELERATED);
SDL_Surface *shape = SDL_CreateRGBSurface(0, 500, 500, 32, 0, 0, 0, 0);
SDL_Rect rect = { .x = 100, .y = 100, .h = 300, .w = 300 };
SDL_FillRect(shape, &rect, SDL_MapRGB(shape->format, 0xff, 0, 0));
SDL_Texture *t = SDL_CreateTextureFromSurface(r, shape);
SDL_RenderClear(r);
SDL_RenderCopy(r, t, 0, 0);
SDL_RenderPresent(r);
SDL_Event ev;
while (SDL_WaitEvent(&ev))
{
switch (ev.type)
{
case SDL_QUIT:
SDL_Quit();
return 0;
case SDL_WINDOWEVENT:
if (ev.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
{
SDL_RenderClear(r);
SDL_RenderCopy(r, t, 0, 0);
SDL_RenderPresent(r);
}
}
}
return 1;
}
compile command:
gcc -std=c11 -Wall -Wextra -Wno-unused-parameter -pedantic -osdlresize sdlresize.c -lSDL2main -lSDL2
Note any error checking and cleanup is skipped just for brevity, the real code is here for reference.
What I get on my Linux machine when resizing the window often looks like this:
In case you can't see the image: the content isn't properly refreshed, it shows some area to the right and the bottom with contents of whatever is below my window on the desktop.
Is there anything wrong in my handling of the SDL_WINDOWEVENT_SIZE_CHANGED? The same thing happens if I handle SDL_WINDOWEVENT_RESIZED instead...