size of display connected via HDMI was'nt automatically detected correctly (xUbuntu)

I have xUbuntu 18.04.4 LTS (XFCE 4.12 + 4.15.0-111 Linux kernel) on the Dell Vostro 3360 laptop.
When I connected the external display (Samsung SyncMaster T240) via VGA cable – all is good and I got such xrandr output:

xrandr -q
***
VGA-1 connected 1920x1200+1366+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
***

But when I connected this one via HDMI cable the size of this display isn’t detected correcltly (in the XFCE Display window it shows as Samsung 7") and I got such output:

***
xrandr -q
HDMI-1 connected 1920x1200+1366+0 (normal left inverted right x axis y axis) 160mm x 90mm
   1920x1200     59.95*+
***

Accordingly, some apps such as Viber or Caliber are displayed with "huge controls".

How I can fix this problem (desirable – not only for this display, but for HDMI-connections at all)?

UPDATED.
for now looks like problem is in EDID-information that is sending by external-display via HDMI (and NO, xrandr --fbmm doesn’t works…)