I have looked deeper and found, that rules for ".x-superboxselect" overwrites by ".ext-strict .x-form-field-trigger-wrap .x-form-text, .ext-strict .x-small-editor .x-form-field-trigger-wrap .x-form-text":
!http://s11.postimage.org/85xrk9aqr/overwrite.png!
dldador created Redmine issue ID 7601
I checked with option "Stack Selected Items" turned off and turned on. Both have this bug.
Here, how shows multi-box tv by default (when edit resource): !http://s13.postimage.org/zf0jp1xfr/only_one_item.png!
I tried to turn off fixed height via chrome dev tools, and this working well: !http://s7.postimage.org/ovlfw3j4b/after.png!
I have looked deeper and found, that rules for ".x-superboxselect" overwrites by ".ext-strict .x-form-field-trigger-wrap .x-form-text, .ext-strict .x-small-editor .x-form-field-trigger-wrap .x-form-text": !http://s11.postimage.org/85xrk9aqr/overwrite.png!
That not all, ".x-form-field-trigger-wrap" fix height too: "see on screeshot":http://s17.postimage.org/eweubgqlb/x_form_field_trigger_wrap.png