Merge branch 'follow' of cgzones/htop

Closes #557

Action.c

@@ -206,12 +206,12 @@ static Htop_Reaction actionSortByTime(State* st) {
 
 static Htop_Reaction actionToggleKernelThreads(State* st) {
    st->settings->hideKernelThreads = !st->settings->hideKernelThreads;
-   return HTOP_RECALCULATE | HTOP_SAVE_SETTINGS;
+   return HTOP_RECALCULATE | HTOP_SAVE_SETTINGS | HTOP_KEEP_FOLLOWING;
 }
 
 static Htop_Reaction actionToggleUserlandThreads(State* st) {
    st->settings->hideUserlandThreads = !st->settings->hideUserlandThreads;
-   return HTOP_RECALCULATE | HTOP_SAVE_SETTINGS;
+   return HTOP_RECALCULATE | HTOP_SAVE_SETTINGS | HTOP_KEEP_FOLLOWING;
 }
 
 static Htop_Reaction actionToggleProgramPath(State* st) {

ProcessList.c

@@ -514,6 +514,7 @@ void ProcessList_rebuildPanel(ProcessList* this) {
    Panel_prune(this->panel);
    int size = ProcessList_size(this);
    int idx = 0;
+   bool foundFollowed = false;
 
    for (int i = 0; i < size; i++) {
       Process* p = ProcessList_get(this, i);
@@ -527,12 +528,19 @@ void ProcessList_rebuildPanel(ProcessList* this) {
       Panel_set(this->panel, idx, (Object*)p);
 
       if (this->following != -1 && p->pid == this->following) {
+         foundFollowed = true;
          Panel_setSelected(this->panel, idx);
          this->panel->scrollV = currScrollV;
       }
       idx++;
    }
 
+   if (this->following != -1 && !foundFollowed) {
+      /* Reset if current followed pid not found */
+      this->following = -1;
+      Panel_setSelectionColor(this->panel, PANEL_SELECTION_FOCUS);
+   }
+
    if (this->following == -1) {
       /* If the last item was selected, keep the new last item selected */
       if (currPos > 0 && currPos == currSize - 1)