Oh yeah, this I will modify in the core theme files and release it with next update.
                                            However, you can fix it for now by adding below code to your custom.css
@media only screen and (min-width: 800px)
.qa-template-user .qa-part-form-activity, .qa-template-user .qa-part-message-list {
    float: left;
    width: 50%;
    padding-right: 10px;
}
@media only screen and (min-width: 800px)
.qa-template-user .qa-part-form-profile {
    float: right;
    width: 50%;
    padding-left: 10px;
}
                                            If still doesn't work (only if doesn't work) than try to use below code
@media only screen and (min-width: 800px)
.qa-template-user .qa-part-form-activity, .qa-template-user .qa-part-message-list {
    float: left !important;
    width: 50% !important;
    padding-right: 10px !important;
}
@media only screen and (min-width: 800px)
.qa-template-user .qa-part-form-profile {
    float: right !important;
    width: 50% !important;
    padding-left: 10px !important;
}