I have a question about playhead.

First I would appreciate it if you could understand that I'm not fluent at English and I'm really unaccustomed to this program.
DaVinci Resolve doesn't support my mother tongue

Anyway what I want to know is this:

I usually cut a video by moving playhead and using razor.
The problem is that I can move playhead between 0 second and 0.23, but between 0.23 and 0.99 I can't move it. For example as the image that I attach, I can move playhead between 01:00:04:00 and 01:00:04:23, but between 01:00:04:23 and 01:00:04:99 I can't move it.
Could you let me know how to move playhead between 0:23 and 0:99? or is there another way to cut a video between 0:23 and 0:99?

Thank you for reading it.

[Peter Chamberlain]

The last two digits are frame count so in a 24fps timeline the next value after 23 is 00