i thought i should investigate that more before filing a bug report, the crashing seems to happen only in this constellation so that i think there are at least two issues (tilemap with very small tiles AND the blend modes being active) playing together to crash the editor.
In fact i think the tilemap has to do a lot with it, with only one layer and the 1*1 tilemap without blend modes the editor also behaves weird (like its a bit tired ^^) without increasing cpu usage it lags at one moment and dont respond and in the other moment its totally normal, zooming in and out seems to trigger that behaviour, but like i said, i have to investigate that more to give usefull information to track this down.
But yes, i think a option to disable blend modes in the editor would help me a lot right now