i found this online:
“The BI’UR HALACHAH (OC 315:7) explains that an umbrella is not similar to a folding chair, because such a chair unfolds right into position. An umbrella, however, is different, because the metal rods keep the umbrella locked in the open position, and these must be clicked into place when unfolding the umbrella. Because of this, opening an umbrella is deemed constructing an Ohel, and not merely putting an object in a different position. “
sounds to me like our modern umbrellas
in addition ive asked two Poskim about this issur and i was told the problem is the issur of ohel