Two weeks ago I created an APEX form and rearranged the fields using "Drag and drop layout".
Last week I installed the APEX IDE Plugin.
Today I noticed that the "drag and drop layout" did not work. After arranging the fields, I tried to click the "Next" button but nothing changed. APEX should proceed to the next screen when you click the NEXT button.
I uninstalled the APEX IDE plugin and tried "drag and drop layout" again; now APEX works as expected.
This information may be helpful:
Apex 4.0 on Oracle 10.2.0.5 on linux 64 bit.
My desktop is CentOS Linux with Firefox 3.6.12