DD has been like this since about 16weeks, has always liked being upright but it started to get very frustrating for her at that age and still is now at 5.5months. We have a door bouncer which is ok for a while and I was thinking of walker but not many places sell them anymore - apparently they're dangerous!
It's v.annoying and only gets worse, DD now constantly arches her back to try and get me to put her up and does sit ups when on her back! She also pulls herself up holding my hair!
On the one hand, I'm told that door bouncers are bad for their hips...
On the other hand, both my DDs loved theirs - and I'm sure they are less of a liability than the baby walkers that are actually mobile. We hung one in the kitchen door to provide entertainment while mummy cooked.