yes, you are quite right, Josh, thank you very much for reply. But mystery is, that it started after some time on quite new Lazarus (1.7/3.1.1/53629M) instance on Mac. Nothing changed in Lazarus installation and suddenly it happened on Mac. I have only one Lazarus on Mac and no changes for two weeks. And no message, nothing - it stopped working.
I moved it to PC and there on older Lazarus (1.6.2/3.0.0/53354) I got a message. There I removed those properties and it started working again.
But on Mac I changed nothing, the line is still here
DesignTimePPI = 72
and Lazarus started working there too. Suddenly. I can not be sure what was a problem, I have no message on Mac.
And by the way when I tried Lazlogger, which is working on PC, I was not successful, maybe is the change in parameters to
--debug-log=/Users/jiricvrk/lazlog.txt
not enough..
Would it be better in such case to run app from terminal, could I get some messages there?
Now I can work again, but I am not sure when It will happen again. And without a PC a have no feedback to see.