As of JEvents v3.4.17 and above (i.e., v3.4.18), the arrow for the Previous Month on the Minical Module is missing when using the "ext" theme. The minical is also no longer centered. Configuring the "Previous Month" option in the module has no effect, although disabling the "Next Month" option still removes the arrow for the Next Month, as expected.
I've tried comparing the calendar.php file in the tmpl/ext directory for discrepancies compared to other templates (i.e. tmpl/flat), but find nothing that stands out as a problem.
JEvents has been updated to v3.4.18 as of Aug 29, 2016
See JEvents Support Information:
PHP Version : 5.6.24
MySQL Version : 5.5.5-10.1.16-MariaDB
Server Information : Linux ezekiel.engr.csufresno.edu 4.6.5-300.fc24.x86_64 #1 SMP Thu Jul 28 01:10:12 UTC 2016 x86_64
Fix jQuery? : Yes
Load JEvents Bootstrap CSS? : Yes
Max Input Vars ? : 1000
Club code set? : No
User Agent : Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36
Joomla : 3.6.2
component_com_jevents : 3.4.18
component_com_jce : 2.5.25
module_mod_jevents_cal : 3.4.18
module_mod_jevents_custom : 3.4.18
module_mod_jevents_filter : 3.4.18
module_mod_jevents_latest : 3.4.18
module_mod_jevents_legend : 3.4.18
module_mod_jevents_switchview : 3.4.18
plugin_content_jevents : 3.4.18
plugin_finder_jevents : 3.4.18 (not enabled)
plugin_search_eventsearch : 3.4.18
plugin_system_gwejson : 3.4.18